PDF/UA rules, explained

Document & metadata20 rules

ISO 14289-1 requirements outside the Matterhorn Protocol

• UA1-6.1-1 File does not start as a PDF 1.0 to 1.7 file

  Checked automatically

  Why it matters

  PDF/UA-1 only covers PDF versions 1.0 to 1.7. A damaged start of file can stop some readers from opening it; a PDF 2.0 file falls under PDF/UA-2 instead.

  How to fix

  1. This comes from the program that made the PDF. Export it again with a current version, as PDF 1.7 if the program lets you choose.
  2. In Acrobat Pro: use the PDF Optimizer to save a copy compatible with an Acrobat version that uses PDF 1.7.

  Matterhorn Protocol 1.1 The file header is not "%PDF-1.n" (n from 0 to 7) followed by an end-of-line marker.

  ISO 14289-1, clause 6.1

Checkpoint 06: Metadata

• 06-001 Document metadata is missing

  Checked automatically Tagafolio fixes this

  Why it matters

  The title, language and PDF/UA claim are stored in metadata. Without it, assistive technology and search tools have less to work with, and the file can't declare PDF/UA.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. In Word: fill in File > Info > Properties > Title, then export the PDF again with tags on.
  2. In Acrobat Pro: enter the title in File > Properties > Description and save the file; Acrobat writes the metadata.

  Matterhorn Protocol 1.1 Document does not contain an XMP metadata stream

  ISO 14289-1, clause 7.1-8

• 06-002 File does not declare that it follows PDF/UA

  Checked automatically Tagafolio fixes this

  Why it matters

  Checkers and some assistive technology use this mark to know the file is meant to meet PDF/UA. Without it, the file can't claim PDF/UA conformance.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. Add the mark only after the file meets the other PDF/UA requirements; a false claim misleads users.
  2. Many programs don't add it. In Acrobat Pro: Preflight's PDF/UA options can add the identification to the file.

  Matterhorn Protocol 1.1 The XMP metadata stream in the Catalog dictionary does not include the PDF/UA identifier.

  ISO 14289-1, clause 5

• 06-003 Document has no title

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers and browser tabs announce the file name instead, which is often unclear. Users with several documents open can't tell them apart.

  How to fix

  Tagafolio fixes this when you choose Fix file and give the document title.

  Or fix it yourself:

  1. In Word or PowerPoint: enter a title in File > Info > Properties > Title, then export the PDF again.
  2. In InDesign: enter a Document Title in File > File Info before exporting.
  3. In Acrobat Pro: enter the title in File > Properties > Description and save the file.

  Matterhorn Protocol 1.1 XMP metadata stream does not contain dc:title

  ISO 14289-1, clause 7.1-8

• 06-004 Document title does not describe the document

  Needs human review

  Why it matters

  A title like "Document1" or a file code tells screen reader users nothing about what they have opened.

  How to fix

  1. Check that the title says what the document is, for example "Annual report 2025", not "untitled", a template name or a file name.
  2. In Word: correct File > Info > Properties > Title, then export the PDF again.
  3. In Acrobat Pro: correct the title in File > Properties > Description and save the file.

  Matterhorn Protocol 1.1 dc:title does not clearly identify the document

  ISO 14289-1, clause 7.1-8

Checkpoint 07: Dictionary

• 07-001 Viewer shows the file name instead of the title

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers announce the window title. A file name such as "rpt_v3_final.pdf" tells users much less than the document's real title.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. In InDesign: in the PDF export's Advanced settings, set Display Title to Document Title.
  2. In Acrobat Pro: choose File > Properties > Initial View > Show: Document Title, then save the file.

  Matterhorn Protocol 1.1 ViewerPreferences dictionary of the Catalog dictionary does not contain a DisplayDocTitle entry.

  ISO 14289-1, clause 7.1-9

• 07-002 Viewer is set to show the file name, not the title

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers announce the window title. A file name such as "rpt_v3_final.pdf" tells users much less than the document's real title.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. In InDesign: in the PDF export's Advanced settings, set Display Title to Document Title.
  2. In Acrobat Pro: choose File > Properties > Initial View > Show: Document Title, then save the file.

  Matterhorn Protocol 1.1 ViewerPreferences dictionary of the Catalog dictionary contains a DisplayDocTitle entry with a value of false.

  ISO 14289-1, clause 7.1-9

Checkpoint 11: Declared Natural Language

• 11-001 Language of the text is not set

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers use the language to choose the voice and pronunciation. Without it, text may be mispronounced.

  How to fix

  Tagafolio fixes this when you choose Fix file and give the document language.

  Or fix it yourself:

  1. In Word: set the language under Review > Language > Set Proofing Language, also for passages in other languages, then export again with tags on.
  2. In Acrobat Pro: set the document language in File > Properties > Advanced > Reading Options > Language, and save.
  3. For passages in another language, set the language in the tag's Properties in the Tags panel.

  Matterhorn Protocol 1.1 Natural language for text in page content cannot be determined.

  ISO 14289-1, clause 7.2-3

• 11-002 Language of image descriptions cannot be determined

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers need the language to pronounce alt text, replacement text and expansions of abbreviations correctly.

  How to fix

  Tagafolio fixes this when you choose Fix file and give the language.

  Or fix it yourself:

  1. In Acrobat Pro: set the document language in File > Properties > Advanced > Reading Options > Language, and save.
  2. If a description is in a different language from the document, set that language in the tag's Properties in the Tags panel.

  Matterhorn Protocol 1.1 Natural language for text in Alt, ActualText and E attributes cannot be determined.

  ISO 14289-1, clause 7.2-3

• 11-003 Language of bookmarks cannot be determined

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers need the language to pronounce bookmark names correctly when users navigate with them.

  How to fix

  Tagafolio fixes this when you choose Fix file and give the language.

  Or fix it yourself:

  1. In Word: set the document language under Review > Language > Set Proofing Language, then export again.
  2. In Acrobat Pro: set the document language in File > Properties > Advanced > Reading Options > Language, and save.

  Matterhorn Protocol 1.1 Natural language in the Outline entries cannot be determined.

  ISO 14289-1, clause 7.2-3

• 11-004 Language of comments and link descriptions cannot be determined

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers need the language to pronounce the descriptions of links, comments and other annotations correctly.

  How to fix

  Tagafolio fixes this when you choose Fix file and give the language.

  Or fix it yourself:

  1. In Word: set the document language under Review > Language > Set Proofing Language, then export again.
  2. In Acrobat Pro: set the document language in File > Properties > Advanced > Reading Options > Language, and save.

  Matterhorn Protocol 1.1 Natural language in the Contents entry for annotations cannot be determined.

  ISO 14289-1, clause 7.2-3

• 11-005 Language of form field descriptions cannot be determined

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers read a form field's description (tooltip) as its label. Without a known language, it may be mispronounced.

  How to fix

  Tagafolio fixes this when you choose Fix file and give the language.

  Or fix it yourself:

  1. In Acrobat Pro: set the document language in File > Properties > Advanced > Reading Options > Language, and save.
  2. Check that each form field's tooltip is written in that language.

  Matterhorn Protocol 1.1 Natural language in the TU entry for form fields cannot be determined.

  ISO 14289-1, clause 7.2-3

• 11-006 Language of the title and metadata cannot be determined

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers need the language to pronounce the document title correctly when the file opens.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. In Word: set the document language under Review > Language > Set Proofing Language, then export again.
  2. In Acrobat Pro: set the document language in File > Properties > Advanced > Reading Options > Language, and save.

  Matterhorn Protocol 1.1 Natural language for document metadata cannot be determined.

  ISO 14289-1, clause 7.2-3

• 11-007 The language is set wrongly

  Needs human review

  Why it matters

  Screen readers pronounce text by the declared language. Spanish text marked as English, for example, is read with English pronunciation and is hard to follow.

  How to fix

  1. Check that the document language matches the main text, and that passages in other languages are marked with their own language.
  2. In Word: correct the language under Review > Language > Set Proofing Language, then export again.
  3. In Acrobat Pro: correct it in File > Properties > Advanced > Reading Options, or in the tag's Properties for single passages.

  Matterhorn Protocol 1.1 Natural language is not appropriate.

  ISO 14289-1, clause 7.2-3

Checkpoint 20: Optional Content

• 20-001 A layer configuration has no name

  Checked automatically Tagafolio fixes this

  Why it matters

  Users who open the layers list, including screen reader users, can't tell the configurations apart when they have no name.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program that made the PDF, often CAD software or InDesign with layers. Export it again with a current version.
  2. In InDesign: if the layers aren't needed in the PDF, turn off "Create Acrobat Layers" when exporting.

  Matterhorn Protocol 1.1 Name entry is missing or has an empty string as its value in an Optional Content Configuration Dictionary in the Configs entry in the OCProperties entry in the Catalog dictionary.

  ISO 14289-1, clause 7.10-1

• 20-002 The default layer configuration has no name

  Checked automatically Tagafolio fixes this

  Why it matters

  Users who open the layers list, including screen reader users, can't identify the default configuration when it has no name.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program that made the PDF, often CAD software or InDesign with layers. Export it again with a current version.
  2. In InDesign: if the layers aren't needed in the PDF, turn off "Create Acrobat Layers" when exporting.

  Matterhorn Protocol 1.1 Name entry is missing or has an empty string as its value in an Optional Content Configuration Dictionary that is the value of the D entry in the OCProperties entry in the Catalog dictionary.

  ISO 14289-1, clause 7.10-1

• 20-003 Layers show or hide themselves automatically

  Checked automatically Tagafolio fixes this

  Why it matters

  Content can appear or disappear without the user knowing, for example print-only layers, so what assistive technology reads may not match what is shown.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program that made the PDF. Avoid print-only or screen-only layers, or export without layers.
  2. In Acrobat Pro: if the layers aren't needed, use Flatten Layers in the Layers panel's options.

  Matterhorn Protocol 1.1 An AS entry appears in an Optional Content Configuration Dictionary.

  ISO 14289-1, clause 7.10-2

Checkpoint 21: Embedded Files

• 21-001 An attached file is missing its file name

  Checked automatically Tagafolio fixes this

  Why it matters

  Without both file name entries, viewers and assistive technology may not show the attachment's name, or show it garbled, especially for non-English names.

  How to fix

  Tagafolio fixes this when you choose Fix file and give a name for each embedded file.

  Or fix it yourself:

  1. Decide on a clear file name for each attachment.
  2. In Acrobat Pro: remove the attachment and attach the file again from the Attachments panel, then save.

  Matterhorn Protocol 1.1 The file specification dictionary for an embedded file does not contain F and UF entries.

  ISO 14289-1, clause 7.11-1

Checkpoint 26: Security

• 26-001 Security settings are incomplete

  Checked automatically

  Why it matters

  Without a permissions setting, assistive technology may be refused access to the text, so screen reader users can't read the document.

  How to fix

  1. In Acrobat Pro: remove the security (File > Properties > Security, Security Method: No Security) and save.
  2. If protection is needed, apply password security again with "Enable text access for screen reader devices for the visually impaired" ticked.

  Matterhorn Protocol 1.1 The file is encrypted but does not contain a P entry in its encryption dictionary.

  ISO 14289-1, clause 7.16-1

• 26-002 Security settings block screen readers

  Checked automatically

  Why it matters

  The file's permissions forbid assistive technology from extracting the text, so screen readers may not be able to read it.

  How to fix

  1. In Acrobat Pro: remove the security (File > Properties > Security, Security Method: No Security) and save.
  2. If protection is needed, apply password security again with "Enable text access for screen reader devices for the visually impaired" ticked.

  Matterhorn Protocol 1.1 The file is encrypted and does contain a P entry but the 10th bit position of the P entry is false.

  ISO 14289-1, clause 7.16-1

Back to the top

Tagging & structure25 rules

Checkpoint 01: Real content tagged

• 01-001 Decorative content is tagged as real content

  Needs human review

  Why it matters

  Screen readers read out decorative lines, background images or ornaments as if they mattered. This clutters the reading.

  How to fix

  1. Check each tagged image or shape: if it is only decoration, it should be an artifact.
  2. In Word: right-click a decorative image, open Alt Text and tick "Mark as decorative", then export the PDF again with "Document structure tags for accessibility" on.
  3. In Acrobat Pro: in the Tags panel, right-click the tag and choose "Change Tag to Artifact".

  Matterhorn Protocol 1.1 Artifact is tagged as real content.

  ISO 14289-1, clause 7.1-1

• 01-002 Meaningful content is hidden from assistive technology

  Needs human review

  Why it matters

  Content marked as decoration is skipped by screen readers, so users miss information that sighted readers see.

  How to fix

  1. Check whether anything marked as an artifact carries information, such as a chart or a note.
  2. In Word: don't mark meaningful images as decorative, and keep real content out of the header and footer; then export the PDF again with tags on.
  3. In Acrobat Pro: select the content with the Reading Order tool and tag it as text or figure.

  Matterhorn Protocol 1.1 Real content is marked as artifact.

  ISO 14289-1, clause 7.1-1

• 01-003 Decorative marking appears inside tagged content

  Checked automatically

  Why it matters

  Assistive technology gets conflicting signals about whether to read this content, so it may skip it or read it wrongly.

  How to fix

  1. This usually comes from the program that made the PDF. Export it again from the source document with a current version and tags on.
  2. In Acrobat Pro: select the affected content with the Reading Order tool and tag it again, either as content or as background.

  Matterhorn Protocol 1.1 Content marked as Artifact is present inside tagged content.

  ISO 14289-1, clause 7.1-1

• 01-004 Tagged content appears inside decorative content

  Checked automatically

  Why it matters

  Assistive technology gets conflicting signals about whether to read this content, so it may skip real information or read decoration.

  How to fix

  1. This usually comes from the program that made the PDF. Export it again from the source document with a current version and tags on.
  2. In Acrobat Pro: select the affected content with the Reading Order tool and tag it again, either as content or as background.

  Matterhorn Protocol 1.1 Tagged content is present inside content marked as Artifact.

  ISO 14289-1, clause 7.1-1

• 01-005 Some content is not tagged at all

  Checked automatically Tagafolio fixes this

  Why it matters

  Untagged content may be skipped or read out of order by screen readers, and can be lost when the page is reflowed for zooming.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. In Word: export with Save As PDF > Options > "Document structure tags for accessibility" on, not "Print to PDF".
  2. In InDesign: use File > Export > Adobe PDF (Print) with "Create Tagged PDF" on.
  3. In Acrobat Pro: in the Tags panel, use Find to locate unmarked content, then tag it or mark it as an artifact.

  Matterhorn Protocol 1.1 Content is neither marked as Artifact nor tagged as real content.

  ISO 14289-1, clause 7.1-2

• 01-006 Content has the wrong type of tag

  Needs human review Tagafolio fixes this

  Why it matters

  Screen reader users navigate by headings, lists and tables. A heading tagged as a paragraph, for example, hides that structure.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. Compare each tag with what the content is: headings, paragraphs, lists, tables, figures; check that table header cells are tagged as headers.
  2. In Word: use the built-in Heading styles, the list buttons and real tables, then export the PDF again with tags on.
  3. In Acrobat Pro: in the Tags panel, open the tag's Properties and change its type.

  Matterhorn Protocol 1.1 The structure type and attributes of a structure element are not semantically appropriate for the structure element. All of the following structure types must be taken into account: <Document>, <Part>, <Art>, <Sect>, <Div>, <BlockQuote>, <Caption>, <TOC>, <TOCI>, <Index>, <NonStruct>, <Private>, <P>, <H>, <H1>, <H2>, <H3>, <H4>, <H5>, <H6>, <L>, <LI>, <Lbl>, <LBody>, <Table>, <TR>, <TH>, <TD>, <THead>, <TBody, <TFoot, <Span>, <Quote>, <Note>, <Reference>, <BibEntry>, <Code>, <Link>, <Annot>, <Ruby>, <Warichu>, <RB>, <RT>, <RP>, <WT>, <WP>, <Figure>, <Formula>, <Form>.

  NOTE 1: Structure type is not semantically appropriate if the nature of the content inside the structure element does not match the structure type of the structure element. NOTE 2: For any non-standard structure types, the standard structure type to which the type is role-mapped shall be used for validation. NOTE 3: Tables are regular when the number of logical cells is equal in each row after accounting for RowSpan and ColSpan attributes. While PDF/UA-1 does not prohibit irregular tables, irregular tables are almost always a strong indicator of improper table structure. It may be a good idea to raise a warning when such tables are encountered, but it is not required by the Matterhorn Protocol. NOTE 4: The value of table cell attributes is a function of the cell’s semantic role in the table’s structure. Therefore, a <TH> cell may not include a Scope attribute with an inappropriate value.

  ISO 14289-1, clause 7.1-2

• 01-007 The file says its tags may be unreliable

  Checked automatically

  Why it matters

  The program that made the PDF flagged its own tags as possibly wrong, so the structure screen readers rely on may not match the content.

  How to fix

  1. This comes from the program that made the PDF, often an older converter. Export it again from the source document with a current version and tags on.
  2. If you can't export again, review all tags in Acrobat Pro's Tags panel and correct them; removing the flag itself needs a tool that edits the file's internal settings.

  Matterhorn Protocol 1.1 Suspects entry has a value of true.

  ISO 14289-1, clause 7.1-11

Checkpoint 02: Role Mapping

• 02-001 Custom tags are not linked to standard tags

  Checked automatically

  Why it matters

  Assistive technology only understands standard tags. A custom tag that doesn't lead to one is ignored or read as plain text.

  How to fix

  1. In InDesign: in each Paragraph Style's Export Tagging settings, choose a standard PDF tag, then export again with "Create Tagged PDF" on.
  2. In Word: base custom styles on built-in styles such as Heading 1, then export again.
  3. In Acrobat Pro: change custom tags to standard ones in the Tags panel, or correct the role map.

  Matterhorn Protocol 1.1 One or more non-standard tag’s mapping does not terminate with a standard type.

  NOTE: Although PDF/UA defines the nomenclature for heading levels above <H6> (<Hn>), these are not standard structure types (as defined in ISO 32000-1) and therefore <Hn> tags must (PDF/UA-1 7.1, paragraph 1) be role-mapped to a standard structure type. According to PDF/UA-1, PDF/UA-conforming processors are expected to ignore such mappings and respect the heading level.

  ISO 14289-1, clause 7.1-3

• 02-002 Custom tags are linked to the wrong standard tags

  Needs human review

  Why it matters

  Screen readers present content by the standard tag it is linked to, so a heading linked to a paragraph tag drops out of heading navigation.

  How to fix

  1. Check that each custom tag points to the standard tag that matches its content, for example a "Title" style to a heading, not a paragraph.
  2. In InDesign: correct the PDF tag in each Paragraph Style's Export Tagging settings, then export again.
  3. In Acrobat Pro: change the tag type in the Tags panel, or correct the role map.

  Matterhorn Protocol 1.1 The mapping of one or more non-standard types is semantically inappropriate.

  ISO 14289-1, clause 7.1-3

• 02-003 Custom tag links go round in a loop

  Checked automatically

  Why it matters

  When custom tags point to each other in a circle, assistive technology can't work out what the content is, and some tools may fail to read the structure.

  How to fix

  1. This comes from the program that made the PDF. Export it again from the source document with a current version and tags on.
  2. In Acrobat Pro: edit the role map so each custom tag points to a standard tag, or change the affected tags to standard ones in the Tags panel.

  Matterhorn Protocol 1.1 A circular mapping exists

  ISO 14289-1, clause 7.1-3

• 02-004 Standard tags are redefined as other tags

  Checked automatically Tagafolio fixes this

  Why it matters

  If a standard tag such as a paragraph is redefined as something else, assistive technology may present the content differently from what the author intended.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program or plug-in that made or tagged the PDF. Export it again from the source document with a current version and tags on.
  2. In Acrobat Pro: remove the entries for standard tags from the role map, and check that the tags still match their content.

  Matterhorn Protocol 1.1 One or more standard types are remapped.

  ISO 14289-1, clause 7.1-4

Checkpoint 09: Appropriate Tags

• 09-001 Content is read in the wrong order

  Needs human review

  Why it matters

  Screen readers and reflow follow the tag order, not the visual layout. Mixed-up columns, sidebars or captions make the text hard to follow.

  How to fix

  1. In Acrobat Pro: compare the order of the tags (Tags panel or Reading Order tool) with the order a sighted reader would follow.
  2. In Word: use real columns and styles instead of floating text boxes, then export again with tags on.
  3. In Acrobat Pro: drag tags into the correct order in the Tags panel.

  Matterhorn Protocol 1.1 Tags are not in logical reading order.

  ISO 14289-1, clause 7.2-1

• 09-002 Tags are placed inside tags where they don't belong

  Needs human review

  Why it matters

  Screen readers announce content by its place in the structure. A table inside a heading, for example, confuses heading navigation and how the table is read.

  How to fix

  1. In Acrobat Pro: look in the Tags panel for tags placed where they make no sense, such as a table inside a heading.
  2. In Word: keep tables, lists and headings separate, not inside text boxes, then export again with tags on.
  3. In Acrobat Pro: drag the tags out to their correct place in the Tags panel.

  Matterhorn Protocol 1.1 Structure elements are nested in a semantically inappropriate manner. (e.g., a table inside a heading).

  ISO 14289-1, clause 7.2-1

• 09-003 A tag does not match the content it holds

  Needs human review

  Why it matters

  Screen readers present content by its tag. A wrong tag, including a custom tag linked to the wrong standard one, gives users a false picture of the document.

  How to fix

  1. Check that each tag fits its content, taking into account which standard tag any custom tag stands for.
  2. In Word: use the built-in Heading styles, list buttons and real tables, then export the PDF again with tags on.
  3. In Acrobat Pro: open the tag's Properties in the Tags panel and change its type.

  Matterhorn Protocol 1.1 The structure type (after applying any role- mapping as necessary) of a structure element is not semantically appropriate.

  ISO 14289-1, clause 7.2-1

• 09-004 Table tags are not structured correctly

  Checked automatically

  Why it matters

  Screen readers need a correct table structure to announce rows, columns and headers. Without it, users hear a stream of cells with no context.

  How to fix

  1. In Word: build tables with Insert > Table, not tabs, and mark the first row as a repeating header row; then export again with tags on.
  2. In Acrobat Pro: fix the tags in the Tags panel so a table holds rows, and each row holds only header and data cells; the Reading Order tool's Table Editor helps with cells.

  Matterhorn Protocol 1.1 A table-related structure element is used in a way that does not conform to the syntax defined in ISO 32000-1, Table 337.

  ISO 14289-1, clause 7.2-1

• 09-005 List tags are not structured correctly

  Checked automatically

  Why it matters

  Screen readers announce lists and the number of items only when the list structure is correct. Otherwise users can't tell where a list starts or ends.

  How to fix

  1. In Word: create lists with the built-in bullet and numbering buttons, not typed dashes or numbers, then export again with tags on.
  2. In Acrobat Pro: in the Tags panel, arrange each list as list items, each holding a label (bullet or number) and the item text.

  Matterhorn Protocol 1.1 A list-related structure element is used in a way that does not conform to Table 336 in ISO 32000-1.

  ISO 14289-1, clause 7.2-1

• 09-006 Table of contents tags are not structured correctly

  Checked automatically

  Why it matters

  Screen readers can present a table of contents as a navigable list only when its structure is correct.

  How to fix

  1. In Word: create the table of contents with References > Table of Contents, then export again with tags on.
  2. In Acrobat Pro: in the Tags panel, make sure the table of contents holds only entries (or nested tables of contents).

  Matterhorn Protocol 1.1 A TOC-related structure element is used in a way that does not conform to Table 333 in ISO 32000-1.

  ISO 14289-1, clause 7.2-1

• 09-007 Pronunciation guide (ruby) tags are not structured correctly

  Checked automatically

  Why it matters

  Ruby text gives the reading of East Asian characters. If its structure is wrong, screen readers may read the base text and its pronunciation together or not at all.

  How to fix

  1. This usually comes from the program that made the PDF. Export it again from the source document with a current version and tags on.
  2. In Acrobat Pro: in the Tags panel, make sure each ruby holds the base text, the ruby text and, optionally, the ruby punctuation.

  Matterhorn Protocol 1.1 A Ruby-related structure element is used in a way that does not conform to Table 338 in ISO 32000-1.

  ISO 14289-1, clause 7.2-1

• 09-008 Inline note (warichu) tags are not structured correctly

  Checked automatically

  Why it matters

  Warichu is an inline note set in two small lines in Japanese text. If its structure is wrong, screen readers may read it out of place or garbled.

  How to fix

  1. This usually comes from the program that made the PDF. Export it again from the source document with a current version and tags on.
  2. In Acrobat Pro: in the Tags panel, make sure each warichu holds its text and, optionally, its punctuation.

  Matterhorn Protocol 1.1 A Warichu-related structure element is used in a way that does not conform to Table 338 in ISO 32000-1.

  ISO 14289-1, clause 7.2-1

Checkpoint 18: Page Headers and Footers

• 18-001 Running headers and footers are read as content

  Needs human review

  Why it matters

  Screen readers repeat page headers, footers and page numbers on every page, interrupting the text.

  How to fix

  1. Check that repeated page elements, such as running titles and page numbers, are marked as artifacts, not tagged.
  2. In Word: put them in the real header and footer (Insert > Header or Footer), not in the body text, then export again with tags on.
  3. In Acrobat Pro: in the Tags panel, right-click their tags and choose "Change Tag to Artifact".

  Matterhorn Protocol 1.1 Headers and footers are not marked as pagination artifacts.

  ISO 14289-1, clause 7.8-1

• 18-002 Headers and footers are not labelled as such

  Needs human review

  Why it matters

  When headers and footers are labelled, assistive technology can offer them on request. Without the label, they can't be told apart from other decoration.

  How to fix

  1. Check that headers and footers are marked as header or footer artifacts.
  2. In Word or InDesign: use the real header and footer features, then export again with a current version and tags on.
  3. In Acrobat Pro: when you change them to artifacts in the Tags panel, choose the pagination type and the header or footer subtype.

  Matterhorn Protocol 1.1 Header or footer artifacts are not classified as Header or Footer subtypes.

  ISO 14289-1, clause 7.8-1

Checkpoint 19: Notes and References

• 19-001 Footnotes or endnotes are not tagged as notes

  Needs human review

  Why it matters

  Screen reader users can't recognise or skip footnotes that look like ordinary text, so notes interrupt the main text or are missed.

  How to fix

  1. Check that each footnote and endnote is tagged as a note.
  2. In Word: create notes with References > Insert Footnote or Insert Endnote, not typed superscript numbers, then export again with tags on.
  3. In Acrobat Pro: change the note's tag type to Note in the Tags panel.

  Matterhorn Protocol 1.1 Footnotes or endnotes are not tagged as <Note>.

  ISO 14289-1, clause 7.9-1

• 19-002 References are not tagged as references

  Needs human review

  Why it matters

  Citations, note markers and cross-references that aren't tagged as references can't be recognised as pointers to other content by assistive technology.

  How to fix

  1. Check that note markers, citations and cross-references (such as "see page 5") are tagged as references.
  2. In Word: insert cross-references with References > Cross-reference rather than typing them, then export again with tags on.
  3. In Acrobat Pro: change their tag type to Reference in the Tags panel.

  Matterhorn Protocol 1.1 References are not tagged as <Reference>.

  ISO 14289-1, clause 7.9-1

• 19-003 A note has no identifier

  Checked automatically

  Why it matters

  Each note needs an identifier so that assistive technology can link it to the place in the text that refers to it.

  How to fix

  This comes from the program that made the PDF. Export it again from the source document with a current version and tags on, using the program's own footnote feature.

  Matterhorn Protocol 1.1 ID entry of the <Note> tag is not present.

  ISO 14289-1, clause 7.9-2

• 19-004 Two or more notes share the same identifier

  Checked automatically

  Why it matters

  When notes share an identifier, assistive technology can't tell which note a reference points to.

  How to fix

  This comes from the program that made the PDF, or from combining several PDFs. Export it again from the source document with a current version and tags on.

  Matterhorn Protocol 1.1 ID entry of the <Note> tag is non-unique.

  ISO 14289-1, clause 7.9-2

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Headings & navigation9 rules

Checkpoint 14: Headings

• 14-001 Headings are not marked as headings

  Needs human review

  Why it matters

  Screen reader users cannot jump between headings or get an overview, and bookmarks cannot be made from headings.

  How to fix

  1. Check in the Tags panel that text that looks like a heading (larger, bold, starting a section) has an H1–H6 tag.
  2. In Word: apply Home > Styles (Heading 1, Heading 2…) to every heading, then save as PDF with tags on.
  3. In InDesign: map heading paragraph styles to H1, H2… with Export Tagging, then export with “Create Tagged PDF”.
  4. In Acrobat Pro: change the tag of each heading in the Tags panel.

  Matterhorn Protocol 1.1 Headings are not tagged.

  ISO 14289-1, clause 7.4-1

• 14-002 The first heading is not a level 1 heading

  Checked automatically

  Why it matters

  Screen reader users rely on heading levels to understand the outline; starting at a lower level suggests missing content above it.

  How to fix

  1. In Word: give the document’s main title or first heading the Heading 1 style, and adjust the levels below it, then export again.
  2. In Acrobat Pro: in the Tags panel, change the first heading tag to H1 and check the levels that follow.

  Matterhorn Protocol 1.1 Does use numbered headings, but the first heading tag is not <H1>.

  ISO 14289-1, clause 7.4.2-1

• 14-003 Heading levels are skipped

  Checked automatically Tagafolio fixes this

  Why it matters

  A jump such as from level 1 to level 3 makes screen reader users think a section is missing and confuses the document outline.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. In Word: apply heading styles in order (Heading 1, then Heading 2, then Heading 3), using formatting rather than a lower level to change appearance, then export again.
  2. In Acrobat Pro: in the Tags panel, change the skipped-level heading tags so each level follows the one above.

  Matterhorn Protocol 1.1 Numbered heading levels in descending sequence are skipped (Example: <H3> follows directly after <H1>).

  ISO 14289-1, clause 7.4-1

• 14-004 Numbered heading tags do not use the standard H1–H6 names

  Needs human review

  Why it matters

  Assistive technology only recognises headings tagged H1, H2 and so on; custom names such as “Heading” or “Title1” are not announced as headings.

  How to fix

  1. Check custom tags in the Tags panel and decide whether each one really is a heading, and of which level.
  2. In InDesign: map heading paragraph styles to H1, H2… in Export Tagging, then export again.
  3. In Acrobat Pro: role map the custom tag to the right H1–H6 tag, or retag the headings directly in the Tags panel.

  Matterhorn Protocol 1.1 Numbered heading tags do not use Arabic numerals and are not role mapped to heading types that do use Arabic numerals.

  NOTE 1: A human is required to validate that the custom structure element is intended to be a heading element. Note 2: The rule requiring Arabic numerals for headings applies to the heading subtype for the structure element or, if role mapped, to its eventual heading target.

  ISO 14289-1, clause 7.4.3-1

• 14-005 Deep headings below level 6 are not tagged

  Needs human review

  Why it matters

  Screen reader users lose the outline when headings at level 7 or deeper are flattened into body text or wrong levels.

  How to fix

  1. Check documents with very deep structure, such as legal texts, and confirm that headings below level 6 are tagged H7, H8 and so on.
  2. In Word: use the Heading 7, Heading 8 and Heading 9 styles for those levels, then export again.
  3. In Acrobat Pro: in the Tags panel, give those headings H7 or deeper tags; consider whether the structure could be simplified.

  Matterhorn Protocol 1.1 Content representing a 7th level (or higher) heading does not use an <H7> (or higher) tag.

  ISO 14289-1, clause 7.4.3-1

• 14-006 A section contains more than one generic heading

  Checked automatically

  Why it matters

  With generic headings, each section may have only one; more than one makes the heading structure ambiguous for screen readers.

  How to fix

  1. This usually comes from the program that made the PDF; export again with numbered headings (H1–H6), which Word and InDesign use by default.
  2. In Acrobat Pro: in the Tags panel, either split the section so each has one H tag, or change the headings to numbered H1–H6 tags.

  Matterhorn Protocol 1.1 A node contains more than one <H> tag.

  ISO 14289-1, clause 7.4.4-1

• 14-007 Generic and numbered headings are mixed

  Checked automatically

  Why it matters

  Mixing the two heading systems leaves screen readers with an inconsistent outline, so heading navigation becomes unreliable.

  How to fix

  1. Export the PDF again from the source with heading styles; Word and InDesign produce numbered headings (H1–H6).
  2. In Acrobat Pro: in the Tags panel, change the generic H tags to numbered H1–H6 tags at the right levels.

  Matterhorn Protocol 1.1 Document uses both <H> and <H#> tags.

  NOTE 3: In weakly-structured documents, headings always take the form <Hn> (e.g., <H1>, <H2>, <Hn>) without intervening whitespace or numerical separators.

  ISO 14289-1, clause 7.4.4-3

Checkpoint 22: Article Threads

• 22-001 Article threads follow the wrong order

  Needs human review

  Why it matters

  Some readers and reflow views follow article threads; if threads jump around, people who zoom or use those views read the text out of order.

  How to fix

  1. Check whether the document has article threads and follow each one to see that it matches the reading order of the text.
  2. In InDesign: correct the order in the Articles panel, then export again.
  3. In Acrobat Pro: use the Article tool to redraw the threads in reading order, or delete them if they are not needed.

  Matterhorn Protocol 1.1 Article threads do not reflect logical reading order.

  ISO 14289-1, clause 7.12-1

Checkpoint 27: Navigation

• 27-001 Long document is hard to navigate

  Why it matters

  There is no automatic test for this; it is covered by headings and bookmarks. Without them, screen reader and keyboard users struggle to move around long documents.

  How to fix

  1. In Word: use heading styles, and add a table of contents for long documents.
  2. In Word: save as PDF with “Create bookmarks using: Headings” and “Document structure tags for accessibility” on.
  3. In Acrobat Pro: check that the bookmarks match the headings and lead to the right places.

  Matterhorn Protocol 1.1 No tests specific to navigation are required; use appropriate semantics. UA1:7.17-1 -- -- 01-006

Back to the top

Text & fonts34 rules

Checkpoint 08: OCR Validation

• 08-001 Scanned text was recognised with many errors

  Needs human review

  Why it matters

  Screen readers read the recognised text, not the picture of the page, so misread words reach listeners as nonsense. Search and copy/paste return wrong words too.

  How to fix

  1. Compare the recognised text with the page image, for example by copying a few paragraphs into a text editor.
  2. If the original document exists, export a new PDF from it instead of using the scan.
  3. In Acrobat Pro: run text recognition again on a clean, high-resolution scan, then correct the remaining errors by hand.

  Matterhorn Protocol 1.1 OCR-generated text contains significant errors.

  ISO 14289-1, clause 7.1-10

• 08-002 Recognised text from a scan has no tags

  Needs human review

  Why it matters

  Without tags, screen readers cannot tell headings, lists or tables apart from body text, and the reading order may be wrong.

  How to fix

  1. Check whether the scanned pages have text recognition but no tag structure, using the Tags panel in Acrobat Pro.
  2. If the original document exists, export a new tagged PDF from it instead of using the scan.
  3. In Acrobat Pro: use automatic tagging, then check and correct the headings, lists, tables and reading order in the Tags panel and the Reading Order tool.

  Matterhorn Protocol 1.1 OCR-generated text is not tagged

  ISO 14289-1, clause 7.1-10

Checkpoint 10: Character Mappings

• 10-001 Some characters cannot be turned into readable text

  Checked automatically

  Why it matters

  Screen readers may skip these characters or read them as nonsense, and copy/paste and search give wrong results.

  How to fix

  1. This usually comes from the font or the program that made the PDF, often with symbol or decorative fonts.
  2. In Word: replace symbol fonts with standard Unicode fonts or inserted symbols, then save as PDF again with “Document structure tags for accessibility” on.
  3. In Acrobat Pro: Preflight font fixups may help, but exporting again from the source is usually the reliable fix.

  Matterhorn Protocol 1.1 Character code cannot be mapped to Unicode.

  ISO 14289-1, clause 7.2-2

Checkpoint 12: Stretchable Characters

• 12-001 Stretched characters are not readable as text

  Needs human review

  Why it matters

  Characters built from several pieces, such as tall brackets in formulas, may be read out as fragments or not at all by screen readers.

  How to fix

  1. Look for large brackets, braces or arrows built from several pieces, and check what a screen reader announces.
  2. In Word: build formulas with the equation editor rather than drawing or assembling symbols by hand, then export again.
  3. In Acrobat Pro: in the Tags panel, give the tag that contains the stretched character an Actual Text with the single character it represents.

  Matterhorn Protocol 1.1 Stretched characters are not represented appropriately.

  ISO 14289-1, clause 7.2-4

Checkpoint 31: Fonts

• 31-001 Font character set information does not match

  Checked automatically

  Why it matters

  Inconsistent font data can make text display or be read out wrongly, especially in Asian-language fonts.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 A Type 0 font dictionary with encoding other than Identity-H and Identity-V has values for Registry in both CIDSystemInfo dictionaries that are not identical.

  ISO 14289-1, clause 7.21.3-1

• 31-002 Font character set information does not match

  Checked automatically

  Why it matters

  Inconsistent font data can make text display or be read out wrongly, especially in Asian-language fonts.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 A Type 0 font dictionary with encoding other than Identity-H and Identity-V has values for Ordering in both CIDSystemInfo dictionaries that are not identical.

  ISO 14289-1, clause 7.21.3.1-1

• 31-003 Font character set version is too old

  Checked automatically

  Why it matters

  The font may lack characters the text needs, so some text may display or be read out wrongly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 A Type 0 font dictionary with encoding other than Identity-H and Identity-V has a value for Supplement in the CIDSystemInfo dictionary of the CID font that is less than the value for Supplement in the CIDSystemInfo dictionary of the CMap.

  ISO 14289-1, clause 7.21.3.1-1

• 31-004 Font is missing its glyph lookup table

  Checked automatically

  Why it matters

  Without it, programs may show the wrong shapes for characters, so text can display incorrectly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 A Type 2 CID font contains neither a stream nor the name Identity as the value of the CIDToGIDMap entry.

  ISO 14289-1, clause 7.21.3.2-1

• 31-005 Font is missing its glyph lookup table

  Checked automatically Tagafolio fixes this

  Why it matters

  Without it, programs may show the wrong shapes for characters, so text can display incorrectly.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 A Type 2 CID font does not contain a CIDToGIDMap entry.

  ISO 14289-1, clause 7.21.3.2-1

• 31-006 Font character mapping is missing

  Checked automatically

  Why it matters

  Without a standard or embedded mapping, programs cannot reliably work out which characters the text contains.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 A CMap is neither listed as described in ISO 32000- 1:2008, 9.7.5.2, Table 118 nor is it embedded.

  ISO 14289-1, clause 7.21.3.3-1

• 31-007 Font text direction settings contradict each other

  Checked automatically

  Why it matters

  Conflicting horizontal and vertical writing settings can make text display or be read out in the wrong way.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The WMode entry in a CMap dictionary is not identical to the WMode value in the CMap stream.

  ISO 14289-1, clause 7.21.3.3-1

• 31-008 Font relies on a non-standard character mapping

  Checked automatically

  Why it matters

  Programs may not have the referenced mapping, so they cannot reliably work out which characters the text contains.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 A CMap references another CMap which is not listed in ISO 32000-1:2008, 9.7.5.2, Table 118.

  NOTE 1: For more information see ISO 32000-1 9.7.5.3, UseCMap entry.

  ISO 14289-1, clause 7.21.3.3-2

• 31-009 A font is not embedded

  Checked automatically Tagafolio fixes this

  Why it matters

  The text may display in a substitute font, with wrong spacing or missing characters, and its characters cannot always be identified reliably.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. In Word: turn on File > Options > Save > “Embed fonts in the file”, or switch to a font that allows embedding, then save as PDF again.
  2. In InDesign or other programs: export with a current PDF export rather than a printer driver, with fonts embedded.
  3. In Acrobat Pro: use Preflight’s fixup to embed missing fonts.
  More detail

  Why it matters

  When a font is not included in the PDF, every viewer replaces it with a font of its own. The replacement can have other character widths, so text overlaps, is cut off or overflows boxes and form fields, and characters the replacement lacks show as empty boxes or disappear. People with low vision or dyslexia are affected most: they rely on clear, predictable text and often zoom, reflow or change colours, which makes a poor replacement worse.

  Symbol fonts (Symbol, ZapfDingbats, Wingdings) draw bullets, check marks, arrows and mathematical signs with ordinary letter codes. Without the font, a check mark can appear as a “4” and a bullet as an “l”, on screen and when the text is read aloud.

  Screen readers, braille displays, read-aloud, copy and paste and reflow all need to know which character each glyph is. A file can provide that without the font, but when both the font and its character map are missing, software has to guess.

  For a common text font such as Arial or Times New Roman with a correct character map, a blind screen-reader user usually notices little: screen readers work from the text and the tags. PDF/UA still requires every font that shows visible text to be embedded, without exception, because only then does the file show and read the same everywhere, and because “missing but probably fine” cannot be checked. Invisible text, such as the hidden text layer of a scanned page, is exempt.

  How to fix

  Create the PDF again with its fonts embedded. Most programs embed fonts by default; if yours does not, look for a font or “PDF/A” option in its PDF export settings (in Microsoft Word: Save As, PDF, Options, “ISO 19005-1 compliant (PDF/A)”). A font whose licence forbids embedding has to be replaced in the source document.

  Tagafolio can include open fonts with exactly the same character widths (Liberation Sans for Arial and Helvetica, Liberation Serif for Times, Liberation Mono for Courier, Carlito for Calibri) when every missing font has one. The text stays where it is; the letters look slightly different. Fonts without such a replacement, for example Myriad Pro or symbol fonts, must be embedded when the PDF is created.

  Matterhorn Protocol 1.1 For a font used by text intended to be rendered the font program is not embedded.

  NOTE 2: A glyph is used for rendering if the text render mode is not 3 (text render mode 3 is used for invisible text).

  ISO 14289-1, clause 7.21.4.1-1

• 31-010 A font’s licence may not allow embedding

  Needs human review

  Why it matters

  This is a legal rather than a reading issue: PDF/UA requires fonts that may be embedded for unlimited viewing, so the file stays readable everywhere.

  How to fix

  1. Check the font’s licence; the embedding flags in the font are only a hint and may not reflect the actual licence terms.
  2. If embedding is not allowed, switch the text to a font licensed for embedding, then export the PDF again.

  Matterhorn Protocol 1.1 A font program is embedded that is not legally embeddable for unlimited, universal rendering.

  NOTE 3: Although machines may detect relevant flags, this may not correspond to actual legal circumstances.

  ISO 14289-1, clause 7.21.4.1-2

• 31-011 An embedded font is missing some characters

  Checked automatically

  Why it matters

  Characters missing from the font may show as blanks or boxes, so sighted readers and people who zoom miss words.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font that has all the characters.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 For a font used by text the font program is embedded but it does not contain glyphs for all of the glyphs referenced by the text used for rendering.

  NOTE 4: A glyph is used for rendering if the text render mode is not 3 (text render mode 3 is used for invisible text).

  ISO 14289-1, clause 7.21.4.1-3

• 31-012 Font character list is incomplete

  Checked automatically

  Why it matters

  The font’s list of characters does not match its contents; this is a technical error that can confuse programs reading the file.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The FontDescriptor dictionary of an embedded Type 1 font contains a CharSet string, but at least one of the glyphs present in the font program is not listed in the CharSet string.

  ISO 14289-1, clause 7.21.4.2-1

• 31-013 Font character list names missing characters

  Checked automatically

  Why it matters

  The font’s list of characters does not match its contents; this is a technical error that can confuse programs reading the file.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The FontDescriptor dictionary of an embedded Type 1 font contains a CharSet string, but at least one of the glyphs listed in the CharSet string is not present in the font program.

  ISO 14289-1, clause 7.21.4.2-2

• 31-014 Font character list is incomplete

  Checked automatically Tagafolio fixes this

  Why it matters

  The font’s list of characters does not match its contents; this is a technical error that can confuse programs reading the file.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The FontDescriptor dictionary of an embedded CID font contains a CIDSet string, but at least one of the glyphs present in the font program is not listed in the CIDSet string.

  ISO 14289-1, clause 7.21.4.2-3

• 31-015 Font character list names missing characters

  Checked automatically

  Why it matters

  The font’s list of characters does not match its contents; this is a technical error that can confuse programs reading the file.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The FontDescriptor dictionary of an embedded CID font contains a CIDSet string, but at least one of the glyphs listed in the CIDSet string is not present in the font program.

  ISO 14289-1, clause 7.21.4.2-4

• 31-016 Character widths in the font data disagree

  Checked automatically Tagafolio fixes this

  Why it matters

  Text may be spaced wrongly, overlap or be cut off, and text selection, copy/paste and reflow can go wrong.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 For one or more glyphs, the glyph width information in the font dictionary and in the embedded font program differ by more than 1/1000 unit.

  ISO 14289-1, clause 7.21.5-1

• 31-017 Font has no standard character lookup table

  Checked automatically

  Why it matters

  Programs may show the wrong characters or none, and text may be read out incorrectly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 A non-symbolic TrueType font is used for rendering, but none of the cmap entries in the embedded font program is a non-symbolic cmap.

  ISO 14289-1, clause 7.21.6-1

• 31-018 Some characters cannot be found in the font

  Checked automatically

  Why it matters

  Programs may show the wrong characters or none, and text may be read out incorrectly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 A non-symbolic TrueType font is used for rendering, but for at least one glyph to be rendered the glyph cannot be looked up by any of the non-symbolic cmap entries in the embedded font program.

  ISO 14289-1, clause 7.21.6-2

• 31-019 Font does not state its character encoding

  Checked automatically

  Why it matters

  Programs have to guess which characters the text contains, so text may display or be read out wrongly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The font dictionary for a non-symbolic TrueType font does not contain an Encoding entry.

  ISO 14289-1, clause 7.21.6-3

• 31-020 Font encoding is incomplete

  Checked automatically

  Why it matters

  Programs have to guess which characters the text contains, so text may display or be read out wrongly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The font dictionary for a non-symbolic TrueType font contains an Encoding dictionary which does not contain a BaseEncoding entry.

  ISO 14289-1, clause 7.21.6-4

• 31-021 Font uses a non-standard character encoding

  Checked automatically

  Why it matters

  Programs may not interpret the encoding the same way, so text may display or be read out wrongly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The value for either the Encoding entry or the BaseEncoding entry in the Encoding dictionary in a non-symbolic TrueType font dictionary is neither MacRomanEncoding nor WinAnsiEncoding.

  ISO 14289-1, clause 7.21.6-5

• 31-022 Font uses unknown character names

  Checked automatically

  Why it matters

  Programs cannot work out which characters these names stand for, so text may be read out or copied wrongly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The Differences array in the Encoding entry in a non-symbolic TrueType font dictionary contains one or more glyph names which are not listed in the Adobe Glyph List.

  ISO 14289-1, clause 7.21.6-6

• 31-023 Font lacks the Unicode lookup table it needs

  Checked automatically

  Why it matters

  Programs may not find the right shapes for some characters, so text may display or be read out wrongly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The Differences array is present in the Encoding entry in a non-symbolic TrueType font dictionary but the embedded font program does not contain a (3,1) Microsoft Unicode cmap.

  ISO 14289-1, clause 7.21.6-7

• 31-024 Symbol font has an encoding it should not have

  Checked automatically

  Why it matters

  The extra setting can make programs show the wrong symbols, so text may display incorrectly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The Encoding entry is present in the font dictionary for a symbolic TrueType font.

  ISO 14289-1, clause 7.21.6-8

• 31-025 Symbol font has no character lookup table

  Checked automatically

  Why it matters

  Programs cannot reliably find the symbols to show, so they may display wrongly or not at all.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The embedded font program for a symbolic TrueType font contains no cmap.

  ISO 14289-1, clause 7.21.6-9

• 31-026 Symbol font lacks the standard symbol lookup table

  Checked automatically

  Why it matters

  Programs may pick the wrong lookup table, so symbols may display wrongly.

  How to fix

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 The embedded font program for a symbolic TrueType font contains more than one cmap, but none of the cmap entries is a (3,0) Microsoft Symbol cmap.

  ISO 14289-1, clause 7.21.6-10

• 31-027 Font text cannot be converted to readable characters

  Checked automatically

  Why it matters

  Without a character mapping, screen readers may read nonsense or nothing, and copy/paste and search fail.

  How to fix

  1. This comes from the program or printer driver that made the PDF, often with symbol or unusual fonts.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a standard Unicode font.
  3. In Acrobat Pro: Preflight font fixups may help, but exporting again from the source is usually the reliable fix.

  Matterhorn Protocol 1.1 A font dictionary does not contain the ToUnicode entry and none of the following is true: ■ the font uses MacRomanEncoding, MacExpertEncoding or WinAnsiEncoding ■ the font is a Type 1 or Type 3 font and the glyph names of the glyphs referenced are all contained in the Adobe Glyph List or the set of named characters in the Symbol font, as defined in ISO 32000-1:2008, Annex D ■ the font is a Type 0 font, and its descendant CIDFont uses Adobe-GB1, Adobe-CNS1, Adobe-Japan1 or Adobe-Korea1 character collections ■ the font is a non-symbolic TrueType font

  ISO 14289-1, clause 7.21.7-1

• 31-028 Some characters map to an empty value

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers, search and copy/paste get no character, or a broken one, where the page shows text.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 One or more Unicode values specified in the ToUnicode CMap are zero (0).

  ISO 14289-1, clause 7.21.7-2

• 31-029 Some characters map to invalid special codes

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers, search and copy/paste get invisible or invalid characters where the page shows text.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program or printer driver that made the PDF, not from your content.
  2. Export the PDF again with a current PDF export and fonts embedded, or use a different font.
  3. In Acrobat Pro: try Preflight’s font fixups and check again.

  Matterhorn Protocol 1.1 One or more Unicode values specified in the ToUnicode CMap are equal to either U+FEFF or U+FFFE.

  ISO 14289-1, clause 7.21.7-3

• 31-030 Text uses characters the font does not have

  Checked automatically Tagafolio fixes some cases

  Why it matters

  These characters show as blanks or boxes, so readers miss them, and screen readers may skip or misread them.

  How to fix

  Some programs, such as Oracle BI Publisher, put a real character in the slot a font keeps for missing characters. Tagafolio fixes that automatically when you choose Fix file: it moves the character to a free slot, and the page looks the same. If the character is really missing from the font, Tagafolio can't add it.

  Or fix it yourself:

  1. Find the affected text and switch it to a font that contains all its characters, for example a common Unicode font.
  2. In Word: change the font, then save as PDF again with fonts embedded.
  3. In Acrobat Pro: exporting again from the source is usually the reliable fix; Preflight cannot add missing characters.

  Matterhorn Protocol 1.1 One or more characters used in text showing operators reference the .notdef glyph.

  ISO 14289-1, clause 7.21.8-1

Back to the top

Images & graphics13 rules

Checkpoint 13: Graphics

• 13-001 A meaningful image is not tagged as a figure

  Needs human review

  Why it matters

  Screen readers skip the image or cannot announce it with a description, so its information is lost.

  How to fix

  1. Check in the Tags panel that each meaningful image, chart or drawing sits in a Figure tag; decorative ones should be artifacts.
  2. In Word: add alt text to each meaningful picture (right-click > View Alt Text) and mark purely decorative ones as decorative, then export again with tags on.
  3. In Acrobat Pro: use the Reading Order tool to tag the image as a Figure, or as Background/Artifact if it is decorative.

  Matterhorn Protocol 1.1 Graphics objects other than text objects and artifacts are not tagged with a <Figure> tag.

  ISO 14289-1, clause 7.3-1

• 13-002 An image link does not describe both picture and destination

  Needs human review

  Why it matters

  Screen reader users hear only what the picture shows or where the link goes, not both.

  How to fix

  1. Find links on images or meaningful backgrounds and read their alternative text.
  2. Judge whether it says where the link leads and what the image conveys, for example “Annual report 2025 (cover image): download page”.
  3. In Word: write this in the picture’s alt text (right-click > View Alt Text), then export again.
  4. In Acrobat Pro: correct the alternate text of the figure inside the link in the Tags panel.

  Matterhorn Protocol 1.1 A link with a meaningful background does not include alternative text describing both the link and the graphic’s purpose.

  ISO 14289-1, clause 7.3-1

• 13-003 A caption is not tagged as a caption

  Needs human review

  Why it matters

  Screen readers cannot connect the caption to its picture or table, so the description is heard as unrelated body text.

  How to fix

  1. Look for text that names or explains a figure or table, such as “Figure 3: …”, and check its tag in the Tags panel.
  2. In Word: add captions with References > Insert Caption, export again, and check in the Tags panel that each caption is tagged Caption.
  3. In Acrobat Pro: in the Tags panel, change the caption’s tag to Caption and keep it next to its figure or table.

  Matterhorn Protocol 1.1 A caption is not tagged with a <Caption> tag.

  ISO 14289-1, clause 7.3-2

• 13-004 An image has no alt text

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen reader users hear only “image”, or nothing, and miss what the picture shows.

  How to fix

  Tagafolio fixes this when you choose Fix file and give a description for each image, or mark it as decoration.

  Or fix it yourself:

  1. Write brief alt text giving the image’s purpose in context, not “image of…”; mark purely decorative images as decorative.
  2. In Word: right-click the picture > View Alt Text, write the description, then save as PDF with “Document structure tags for accessibility” on.
  3. In InDesign: set alt text in Object Export Options, then export with “Create Tagged PDF”.
  4. In Acrobat Pro: add the alternate text in the Figure tag’s properties in the Tags panel.

  Matterhorn Protocol 1.1 <Figure> tag alternative or replacement text missing.

  ISO 14289-1, clause 7.3-3

• 13-005 An image uses replacement text instead of a description

  Needs human review

  Why it matters

  Replacement text is read as if it were the words on the page, so a screen reader user may not know an image is there.

  How to fix

  1. For each figure with Actual Text, judge whether it is a picture that needs describing (use alternate text) or text drawn as a picture (Actual Text is right).
  2. In Acrobat Pro: in the Tags panel, open the Figure tag’s properties, move the description from Actual Text to Alternate Text and clear Actual Text.

  Matterhorn Protocol 1.1 ActualText used for a <Figure> for which alternative text is more appropriate.

  ISO 14289-1, clause 7.3-4

• 13-006 Parts of one image are tagged separately

  Needs human review

  Why it matters

  Screen reader users hear several fragments, such as lines and shapes of one diagram, instead of one image with a single description.

  How to fix

  1. Look for diagrams, logos or charts split into several Figure tags whose pieces mean nothing on their own.
  2. In Word or PowerPoint: group the shapes or turn the drawing into one picture, give it one alt text, then export again.
  3. In Acrobat Pro: in the Tags panel, move the pieces into one Figure tag with one alternate text.

  Matterhorn Protocol 1.1 Graphics objects that possess semantic value only within a group of graphics objects is tagged on its own.

  ISO 14289-1, clause 7.3-5

• 13-007 Content is an image where real text would work better

  Needs human review

  Why it matters

  Text, tables or forms shown as pictures cannot be resized, reflowed, searched or navigated, and alt text is a poor substitute for long content.

  How to fix

  1. Look for images of text, tables, lists or charts whose data could be given as real content.
  2. In Word: replace the image with real text, a real table or a chart with its data, then export again.
  3. If an image must stay, add alt text and give the full information as text nearby.

  Matterhorn Protocol 1.1 A more accessible representation is not used.

  ISO 14289-1, clause 7.3-6

• 13-008 An image of text lacks the text itself

  Needs human review

  Why it matters

  When a picture shows words, such as a stylised title, screen readers need those words as text to read them in the flow of the page.

  How to fix

  1. Find figures that are really words, such as stylised headings or word marks, and check whether they carry Actual Text.
  2. In Word or InDesign: replace the picture with real, styled text where you can, then export again.
  3. In Acrobat Pro: in the Tags panel, open the Figure tag’s properties and enter the exact words as Actual Text.

  Matterhorn Protocol 1.1 ActualText not present when a <Figure> is intended to be consumed primarily as text.

  ISO 14289-1, clause 7.3-4

Checkpoint 17: Mathematical Expressions

• 17-001 A formula is not tagged as a formula

  Needs human review

  Why it matters

  Screen readers read mathematics as scattered symbols or skip it, so the meaning of equations is lost.

  How to fix

  1. Look for equations and mathematical expressions and check in the Tags panel that each is in a Formula tag.
  2. In Word: write equations with the equation editor (Insert > Equation) rather than as images or plain symbols, then export again.
  3. In Acrobat Pro: in the Tags panel, tag each expression as Formula and give it alternate text.

  Matterhorn Protocol 1.1 Content is a mathematical expression but is not tagged with a <Formula> tag.

  ISO 14289-1, clause 7.7-1

• 17-002 A formula has no text description

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen reader users cannot tell what the formula says without a text version of it.

  How to fix

  Tagafolio fixes this when you choose Fix file and give a description of each formula.

  Or fix it yourself:

  1. Write the formula as it would be read aloud, for example “x equals minus b plus or minus the square root of b squared minus 4 a c, all over 2 a”.
  2. In Acrobat Pro: in the Tags panel, open the Formula tag’s properties and enter that text as alternate text.

  Matterhorn Protocol 1.1 <Formula> tag is missing an Alt attribute.

  ISO 14289-1, clause 7.7-1

• 17-003 Symbols in a formula cannot be turned into text

  Checked automatically

  Why it matters

  Screen readers and copy/paste get wrong or missing characters for the mathematical symbols.

  How to fix

  1. This usually comes from symbol fonts or the program that made the PDF.
  2. In Word: write equations with the equation editor (which uses the Unicode font Cambria Math) instead of symbol fonts, then export again.
  3. In Acrobat Pro: Preflight font fixups may help, but exporting again from the source is usually the reliable fix.

  Matterhorn Protocol 1.1 Unicode mapping requirements are not met.

  ISO 14289-1, clause 7.7-2

Checkpoint 30: XObjects

• 30-001 A page pulls in content from another file

  Checked automatically

  Why it matters

  The content depends on an external file that may be missing, so it may not display and assistive technology cannot read it.

  How to fix

  This comes from the program that made the PDF: create the PDF again from the source so all content is inside the file, then check that every page shows correctly.

  Matterhorn Protocol 1.1 A reference XObject is present.

  ISO 14289-1, clause 7.20-1

• 30-002 Tagged repeated content is reused across pages

  Checked automatically

  Why it matters

  When the same tagged item, such as a logo or header, is reused on several pages, its tags point to several places at once and screen readers may read it wrongly or repeatedly.

  How to fix

  1. This usually comes from the program that made the PDF; export again with a current version and tags on.
  2. In Acrobat Pro: if the repeated item is decorative, such as a logo in every header, mark it as an artifact.

  Matterhorn Protocol 1.1 Form XObject contains MCIDs and is referenced more than once.

  ISO 14289-1, clause 7.20-2

Back to the top

Tables & lists8 rules

Checkpoint 15: Tables

• 15-001 A row header is not marked as a header

  Needs human review

  Why it matters

  Screen reader users hear table cells without the row label, so they cannot tell what each value refers to.

  How to fix

  1. Check each table for cells, usually the first column, that label their row.
  2. In Word: keep the labels in the first column and turn on "First Column" in Table Design, then export the PDF again with tags on.
  3. In Acrobat Pro: open the Reading Order tool's Table Editor and set those cells as header cells with Row scope.

  Matterhorn Protocol 1.1 A row has a header cell, but that header cell is not tagged as a header.

  ISO 14289-1, clause 7.5-1

• 15-002 A column header is not marked as a header

  Needs human review

  Why it matters

  Screen reader users hear cells without their column label, so values lose their meaning.

  How to fix

  1. In Word: select the header row, turn on Table Properties > Row > "Repeat as header row at the top of each page", then export the PDF again with tags on.
  2. In InDesign: convert the top rows to header rows and export with "Create Tagged PDF".
  3. In Acrobat Pro: in the Reading Order tool's Table Editor, set those cells as header cells with Column scope.

  Matterhorn Protocol 1.1 A column has a header cell, but that header cell is not tagged as a header.

  ISO 14289-1, clause 7.5-1

• 15-003 A table header does not say whether it labels a row or column

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen readers may guess wrongly which cells a header applies to, so users hear the wrong labels when moving through the table.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. In Word: use Table Design's "Header Row" and "First Column" options and the repeat-header-row setting, then export the PDF again with tags on.
  2. In Acrobat Pro: open the Reading Order tool's Table Editor, open each header cell's properties and set its scope to Row or Column.

  Matterhorn Protocol 1.1 In a table not organized with Headers attributes and IDs, a <TH> cell does not contain a Scope attribute.

  ISO 14289-1, clause 7.5-2

• 15-004 Content that is not a table is tagged as a table

  Needs human review

  Why it matters

  Screen readers announce rows and columns that do not exist, which makes simple content slow and confusing to read.

  How to fix

  1. Check whether each tagged table holds real data in rows and columns or only lays out text or images.
  2. In Word: replace layout tables with normal paragraphs, columns or text boxes, then export the PDF again with tags on.
  3. In Acrobat Pro: in the Tags panel, change the table's tags to suitable ones, such as paragraphs or a list.

  Matterhorn Protocol 1.1 Content is tagged as a table for information that is not organized in rows and columns.

  ISO 14289-1, clause 7.5-3

• 15-005 It is unclear which header belongs to a cell

  Needs human review

  Why it matters

  Screen reader users cannot tell which labels apply to a value, so they may misread the data.

  How to fix

  1. Look for complex tables: merged cells, several header rows or headers mid-table.
  2. In Word: split complex tables into simpler ones with one header row each where possible, then export the PDF again with tags on.
  3. In Acrobat Pro: in the Reading Order tool's Table Editor, set each header cell's scope, or give headers IDs and link data cells to them in the cell properties.

  Matterhorn Protocol 1.1 A given cell’s header cannot be unambiguously determined.

  ISO 14289-1, clause 7.5-2

Checkpoint 16: Lists

• 16-001 A numbered list does not say how it is numbered

  Needs human review

  Why it matters

  Screen reader users may not hear that the list is numbered or in what style, which matters when the text refers to "step 3" or "item b".

  How to fix

  1. In Word: create the list with the built-in Numbering button rather than typing numbers, then export the PDF again with tags on.
  2. In Acrobat Pro: open the properties of the list's L tag in the Tags panel and add a list numbering attribute that matches the visible numbering.

  Matterhorn Protocol 1.1 List is an ordered list, but no value for the ListNumbering attribute is present.

  ISO 14289-1, clause 7.6-1

• 16-002 A numbered list has an invalid numbering type

  Needs human review

  Why it matters

  Screen readers may announce the list numbering wrongly or not at all.

  How to fix

  1. Check that each numbered list uses numbers, upper or lower case letters, or upper or lower case Roman numerals, and that its tag says which one.
  2. In Word: re-create the list with the built-in Numbering button, then export the PDF again with tags on.
  3. In Acrobat Pro: open the properties of the list's L tag in the Tags panel and correct its list numbering attribute.

  Matterhorn Protocol 1.1 List is an ordered list, but the ListNumbering value is not one of the following: Decimal, UpperRoman, LowerRoman, UpperAlpha, LowerAlpha.

  ISO 14289-1, clause 7.6-1

• 16-003 A list is not tagged as a list

  Needs human review

  Why it matters

  Screen reader users are not told that items form a list or how many items it has.

  How to fix

  1. Look for content that looks like a list (bullets, numbers, dashes) but is tagged as paragraphs.
  2. In Word: use the built-in Bullets or Numbering buttons instead of typed characters or tabs, then export the PDF again with tags on.
  3. In Acrobat Pro: in the Tags panel, change the items to a list structure (L, LI, Lbl and LBody tags).

  Matterhorn Protocol 1.1 Content is a list but is not tagged as a list.

  ISO 14289-1, clause 7.6-2

Back to the top

Forms, links & annotations22 rules

Checkpoint 23: Digital Signatures

• 23-001 Signature fields must follow the form field rules

  Why it matters

  Screen reader and keyboard users need to find a signature field, know what it is for and reach it in the right order.

  How to fix

  1. Check that each signature field is tagged as a form field and has a short name that describes it, for example "Applicant's signature".
  2. In Acrobat Pro: in Prepare Form, open the signature field's properties and fill in its Tooltip.
  3. Check the other form field rules for these fields, such as those under checkpoint 28.

  Matterhorn Protocol 1.1 No test specific to digital signatures is required, however other provisions apply (form fields). UA1:7.13-1 -- -- 01-006

Checkpoint 24: Non-Interactive Forms

• 24-001 A printed-style form is not marked as a form

  Needs human review

  Why it matters

  Screen reader users do not hear that boxes, checkboxes or answer areas are form elements, or whether a checkbox is ticked.

  How to fix

  1. Look for non-fillable forms that show checkboxes, radio buttons or answer boxes.
  2. Where possible, make the form fillable instead: in Acrobat Pro, use Prepare Form to add real fields with tooltips.
  3. Otherwise, in Acrobat Pro, give the tags of these elements a print field attribute that states their role (for example checkbox) and state, in the Tags panel's tag properties.

  Matterhorn Protocol 1.1 Non-interactive forms are not tagged with the PrintFields attribute.

  ISO 14289-1, clause 7.14-1

Checkpoint 25: XFA

• 25-001 The form is a dynamic XFA form

  Checked automatically

  Why it matters

  Dynamic XFA forms are built by the viewer when opened, so most PDF readers and assistive technologies cannot show or read them reliably.

  How to fix

  1. This comes from the forms program that made the file, such as Adobe LiveCycle Designer.
  2. In that program: save the form as a static PDF form instead of a dynamic one, with tagging on.
  3. Alternatively, rebuild the form as a standard fillable PDF: export the layout from Word with tags on, then add fields in Acrobat Pro with Prepare Form.

  Matterhorn Protocol 1.1 File contains the dynamicRender element with value “required” .

  ISO 14289-1, clause 7.15-1

Checkpoint 28: Annotations

• 28-001 A comment, link or field is read in the wrong order

  Needs human review

  Why it matters

  Screen reader and keyboard users meet the item at the wrong place, out of context.

  How to fix

  1. Check that each link, form field and comment appears in the tag structure next to the text it belongs to.
  2. In Acrobat Pro: in the Tags panel, drag the tag that holds the item to its right place in the reading order.
  3. In Acrobat Pro: in the page properties, set Tab Order to "Use Document Structure" so keyboard order follows the tags.

  Matterhorn Protocol 1.1 An annotation is not in correct reading order.

  ISO 14289-1, clause 7.18.1-2

• 28-002 A comment or other annotation is not tagged

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen reader users may never reach comments, stamps or other annotations because they are missing from the tag structure.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This usually happens when comments or stamps are added to an already tagged PDF.
  2. In Acrobat Pro: in the Tags panel, place each such annotation inside its own Annot tag at the right point in the reading order.
  3. Remove comments that are no longer needed before publishing the document.

  Matterhorn Protocol 1.1 An annotation, other than of subtype Widget, Link and PrinterMark, is not a direct child of an <Annot> structure element.

  ISO 14289-1, clause 7.18.1-2

• 28-003 An annotation is used only for visual formatting

  Needs human review

  Why it matters

  Screen reader users hear meaningless annotations, or miss the meaning the visual effect gives sighted readers.

  How to fix

  1. Look for highlights, lines or boxes added as annotations to style the page.
  2. In Word or InDesign: create the visual effect as part of the page content instead, then export the PDF again with tags on.
  3. If the effect carries meaning, for example "highlighted items are new", also state it in the text.
  4. Then delete those annotations in Acrobat Pro.

  Matterhorn Protocol 1.1 An annotation is used for visual formatting but is not tagged according to its semantic function.

  ISO 14289-1, clause 7.18.1-3

• 28-004 A comment or annotation has no text description

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen reader users hear that an annotation is there but not what it is or says.

  How to fix

  Tagafolio fixes this when you choose Fix file and give a description of each annotation.

  Or fix it yourself:

  1. Give each annotation a short description of its purpose or content, for example "Approved stamp" or the comment text.
  2. In Acrobat Pro: open the annotation's properties and add the text, or add alternate text on its Annot tag in the Tags panel.
  3. Remove annotations that are not needed in the published document.

  Matterhorn Protocol 1.1 An annotation, other than of subtype Widget, does not have a Contents entry and does not have an alternative description (in the form of an Alt entry in the enclosing structure element).

  ISO 14289-1, clause 7.18.1-4

• 28-005 A form field has no accessible name

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen reader users hear only "edit text" or "checkbox" and do not know what to enter.

  How to fix

  Tagafolio fixes this when you choose Fix file and give a name for each form field.

  Or fix it yourself:

  1. Decide a short name for each field that matches its visible label, for example "Date of birth (DD/MM/YYYY)".
  2. In Acrobat Pro: in Prepare Form, open each field's properties and enter that name in Tooltip.
  3. For radio buttons, name the group by the question and each button by its option.

  Matterhorn Protocol 1.1 A form field does not have a TU entry and does not have an alternative description (in the form of an Alt entry in the enclosing structure element).

  ISO 14289-1, clause 7.18.1-4

• 28-006 The PDF uses a non-standard kind of annotation

  Checked automatically

  Why it matters

  Assistive technologies may not recognise the annotation, so its content can be skipped or announced wrongly.

  How to fix

  1. This comes from the program or plug-in that made the PDF, which added a custom annotation type.
  2. Check whether the annotation is needed; if not, remove it, for example by exporting again without it.
  3. If it is needed, replace it with a standard comment, link or field, and make sure it is tagged with a text description.

  Matterhorn Protocol 1.1 An annotation with subtype undefined in ISO 32000 does not meet 7.18.1.

  ISO 14289-1, clause 7.18.2-1

• 28-007 The PDF contains print trapping annotations

  Checked automatically

  Why it matters

  Trapping data is for commercial printing only and is not allowed in an accessible PDF; it adds nothing for readers.

  How to fix

  1. This comes from print production software that added trapping to the file.
  2. Export a separate PDF for the screen without trapping, for example from InDesign with a screen PDF preset and "Create Tagged PDF" on.
  3. Keep the trapped version only for the printer.

  Matterhorn Protocol 1.1 An annotation of subtype TrapNet exists.

  ISO 14289-1, clause 7.18.2-2

• 28-008 A page does not set its keyboard tab order

  Checked automatically Tagafolio fixes this

  Why it matters

  Keyboard and screen reader users may move through links and fields in an order that does not match the reading order.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program that made the PDF.
  2. In Acrobat Pro: open Page Thumbnails, select all pages, open Page Properties and set Tab Order to "Use Document Structure".

  Matterhorn Protocol 1.1 A page containing an annotation does not contain a Tabs entry.

  ISO 14289-1, clause 7.18.3-1

• 28-009 A page's tab order does not follow the document structure

  Checked automatically Tagafolio fixes this

  Why it matters

  Keyboard and screen reader users may jump between links and fields in an order that differs from the reading order.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program that made the PDF, which set the tab order by rows, columns or another order.
  2. In Acrobat Pro: open Page Thumbnails, select all pages, open Page Properties and set Tab Order to "Use Document Structure".

  Matterhorn Protocol 1.1 A page containing an annotation has a Tabs entry with a value other than S.

  ISO 14289-1, clause 7.18.3-1

• 28-010 A form field is not tagged as a form field

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen reader users may not find the field in the reading order, or hear it without its context.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This often happens when fields are added after the PDF was tagged.
  2. In Acrobat Pro: in the Tags panel, place each field inside a Form tag at the right point in the reading order.

  Matterhorn Protocol 1.1 A widget annotation is not nested within a <Form> tag.

  ISO 14289-1, clause 7.18.4-1

• 28-011 A link is not tagged as a link

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen reader users may not hear that text is a link, or may not be able to find and follow it.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. In Word: create links with Insert > Link and meaningful link text, then export the PDF again with tags on.
  2. In Acrobat Pro: in the Tags panel, place each link inside a Link tag together with its visible text, at the right point in the reading order.

  Matterhorn Protocol 1.1 A link annotation is not nested within a <Link> tag.

  ISO 14289-1, clause 7.18.5-1

• 28-012 A link has no description

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen reader users may hear only the web address, or nothing useful, when they move through the links.

  How to fix

  Tagafolio fixes this when you choose Fix file and give a description of each link.

  Or fix it yourself:

  1. Decide a short description for each link that says where it goes, for example "Annual report 2025 (PDF)" or "Email the help desk".
  2. In Word: use Insert > Link with meaningful link text and a ScreenTip, then export the PDF again with tags on.
  3. In Acrobat Pro: add the description as alternate text on the Link tag in the Tags panel.

  Matterhorn Protocol 1.1 A link annotation does not include an alternate description in its Contents entry.

  ISO 14289-1, clause 7.18.5-2

• 28-013 An image map's links work only by clicking positions

  Needs human review

  Why it matters

  Keyboard and screen reader users cannot use links that depend on clicking a point in an image.

  How to fix

  1. Check images that act as maps or diagrams where clicking different areas leads to different places.
  2. Provide the same destinations as ordinary text links, for example a list of links next to the image.
  3. In Word or InDesign: add that list of links in the source, then export the PDF again with tags on.

  Matterhorn Protocol 1.1 An IsMap entry is present with a value of true but the functionality is not provided in some other way.

  ISO 14289-1, clause 7.18.5-3

• 28-014 An embedded video or audio clip does not state its format

  Checked automatically

  Why it matters

  Without the media type, viewers and assistive technologies may not be able to play the clip or offer an alternative.

  How to fix

  1. This comes from the program that inserted the media into the PDF.
  2. In Acrobat Pro: delete the clip and insert it again with Acrobat's own media tools.
  3. Check afterwards that the clip plays and has a text description.

  Matterhorn Protocol 1.1 CT entry is missing from the media clip data dictionary.

  ISO 14289-1, clause 7.18.6.2-1

• 28-015 An embedded video or audio clip has no text description

  Checked automatically

  Why it matters

  Screen reader users are not told what the clip is about before deciding to play it.

  How to fix

  1. Write a short description of the clip, for example "Video: how to complete the application form, 3 minutes".
  2. This description is stored by the program that inserted the media; if it does not ask for one, insert the clip again with a tool that does.
  3. Also place a transcript or summary of the clip in the document text.

  Matterhorn Protocol 1.1 Alt entry is missing from the media clip data dictionary.

  ISO 14289-1, clause 7.18.6.2-1

• 28-016 An attached file is not described properly

  Checked automatically Tagafolio fixes this

  Why it matters

  Screen reader users cannot tell what an attached file is or what it contains, and some viewers may not show its name correctly.

  How to fix

  Tagafolio fixes this automatically when you choose Fix file.

  Or fix it yourself:

  1. This comes from the program that attached the file.
  2. In Acrobat Pro: remove the attachment, attach the file again and add a description in its properties.
  3. Give attached files clear names, for example "Budget-2026.xlsx".

  Matterhorn Protocol 1.1 File attachment annotations do not conform to 7.11.

  ISO 14289-1, clause 7.18.7-1

• 28-017 Printer's marks are part of the reading order

  Checked automatically

  Why it matters

  Screen reader users may hear crop marks or colour bars, which are meant only for the printer.

  How to fix

  1. This comes from exporting a print PDF with printer's marks.
  2. In InDesign: export a separate PDF for the screen with all printer's marks turned off and "Create Tagged PDF" on.
  3. In Acrobat Pro: delete the printer's marks' tags from the Tags panel, or remove the marks.

  Matterhorn Protocol 1.1 A PrinterMark annotation is included in the logical structure.

  ISO 14289-1, clause 7.18.8-1

• 28-018 Printer's marks are not marked as decorative

  Checked automatically

  Why it matters

  Screen reader users may hear crop marks or colour bars, which are meant only for the printer.

  How to fix

  1. This comes from the program that added the printer's marks to the PDF.
  2. In InDesign: export a separate PDF for the screen with all printer's marks turned off and "Create Tagged PDF" on.
  3. Keep the version with printer's marks only for the printer.

  Matterhorn Protocol 1.1 The appearance stream of a PrinterMark annotation is not marked as Artifact.

  ISO 14289-1, clause 7.18.8-2

Checkpoint 29: Actions

• 29-001 A script needs keys pressed with precise timing

  Needs human review

  Why it matters

  People with motor impairments, and people using switches or speech input, may not be able to press keys quickly or in a precise rhythm.

  How to fix

  1. Check the document's form and button scripts for anything that depends on how fast or how long keys are pressed.
  2. Change the script so it works at any typing speed, or give a way to turn off or extend the time limit.
  3. In Acrobat Pro: edit the scripts on the form fields and the document-level JavaScript.

  Matterhorn Protocol 1.1 A script requires specific timing for individual keystrokes.

  ISO 14289-1, clause 7.19-1

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Colour, flashing & sound7 rules

Checkpoint 03: Flickering

• 03-001 A button or link makes content flash

  Needs human review

  Why it matters

  Rapid flashing can trigger seizures in people with photosensitive epilepsy.

  How to fix

  1. Check buttons, links and page actions that show, hide or change content for anything that flashes more than three times a second.
  2. Remove or slow down any action that makes content blink or flash, for example repeatedly showing and hiding a field.
  3. In Acrobat Pro: open the properties of the button or link and edit or delete the action on its Actions tab.

  Matterhorn Protocol 1.1 One or more Actions lead to flickering.

  ISO 14289-1, clause 7.1-5

• 03-002 A video or animation contains flashing content

  Needs human review

  Why it matters

  Flashing more than three times a second can trigger seizures in people with photosensitive epilepsy.

  How to fix

  1. Play every embedded video or animation and look for flashes, strobe effects or rapid changes between light and dark.
  2. Edit the video in its source to remove or reduce the flashing, then replace it in the document.
  3. If the flashing cannot be removed, place a clear warning before the video and do not let it play automatically.

  Matterhorn Protocol 1.1 One or more multimedia objects contain flickering content.

  ISO 14289-1, clause 7.1-5

• 03-003 A script makes content flash

  Needs human review

  Why it matters

  Flashing more than three times a second can trigger seizures in people with photosensitive epilepsy and distracts others.

  How to fix

  1. Check the document's scripts for anything that changes colours, visibility or content repeatedly on a timer.
  2. In Acrobat Pro: review the document-level JavaScript and the scripts on fields and buttons, and remove or slow down any flashing effect.
  3. Test the result by opening the document and using its forms and buttons.

  Matterhorn Protocol 1.1 One or more JavaScript actions lead to flickering.

  ISO 14289-1, clause 7.1-5

Checkpoint 04: Color and Contrast

• 04-001 Meaning is shown only by colour or layout

  Needs human review

  Why it matters

  Blind, colour-blind and low-vision people may miss information shown only by colour, contrast, bold text or position.

  How to fix

  1. Look for meaning carried only by colour or formatting, such as red for overdue items or chart lines told apart only by colour.
  2. Add the meaning in text too, for example the word "Overdue" or labels in charts.
  3. Check text contrast (at least 4.5:1 for normal text).
  4. In Word or PowerPoint: make the changes, then export the PDF again with tags on.

  Matterhorn Protocol 1.1 Information is conveyed by contrast, color, format or layout, or some combination thereof but the content is not tagged to reflect all meaning conveyed by the use of contrast, color, format or layout, or some combination thereof.

  ISO 14289-1, clause 7.1-6

Checkpoint 05: Sound

• 05-001 A video or audio clip has no transcript or captions

  Needs human review

  Why it matters

  Deaf and hard-of-hearing people cannot hear the audio, and some screen reader users cannot operate the player.

  How to fix

  1. Check every embedded video or audio clip for speech or sounds that carry information.
  2. Provide captions for video and a text transcript for the audio, either in the document next to the clip or as a clearly linked alternative.
  3. In Word or PowerPoint: add the transcript text near the media in the source, then export the PDF again with tags on.

  Matterhorn Protocol 1.1 Media annotation present, but audio content not available in another form.

  NOTE 1: An example of another form is a transcript.

  ISO 14289-1, clause 7.1-7

• 05-002 A sound clip has no text alternative

  Needs human review

  Why it matters

  Deaf and hard-of-hearing people cannot hear the sound, so they miss whatever information it carries.

  How to fix

  1. Find sound clips attached to the page, for example a sound that plays from an icon or a comment.
  2. Write a transcript or a description of the sound and place it in the document near the clip.
  3. If the sound adds nothing, remove it from the document.

  Matterhorn Protocol 1.1 Audio annotation present, but content not available in another form.

  NOTE 2: An example of another form is a transcript.

  ISO 14289-1, clause 7.1-7

• 05-003 A script beeps without a visible message

  Needs human review

  Why it matters

  Deaf and hard-of-hearing people, and anyone with the sound off, will not notice an alert given only by a beep.

  How to fix

  1. Check the document's scripts, especially form validation, for beeps used as warnings.
  2. Make sure every beep comes with a visible text message that explains the problem, or replace the beep with that message.
  3. In Acrobat Pro: edit the scripts on the form fields and the document-level JavaScript to add the message.

  Matterhorn Protocol 1.1 JavaScript uses beep function but does not provide another means of notification.

  ISO 14289-1, clause 7.1-7

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