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PDF/UA-1 Accessibility Validators Comparison Table

Compare Free PDF/UA-1 Accessibility Checkers

“True accessibility isn’t about passing every check — it’s about ensuring your PDF can be understood by everyone”

How to Read the Comparison Table…

This table compares the results of several common free PDF/UA-1 compliance validators/checkers – veraPDF, Adobe Preflight (PDF/UA), PAC, and CommonLook PDF Validator.
Each validator was run in error-only mode, meaning that only failed checks were considered. Warnings and quality messages were excluded to keep the comparison focused on true non-conformances. Each validator uses its own way to indicate the outcome of a compliance check. In this comparison, only failed checks were analyzed, while “x” mean that no errors were found.

For each tested PDF file, the table shows whether and how the validators detected errors.
The color coding helps you quickly understand the level of agreement between tools:

  • 🔴 Red – The validators produced different results. At least one validator either did not detect any error or reported a completely different issue than the others.
  • 🟢 Green – All validators agreed on the result and reported the same error type for the file.
  • 🟠 Orange – The validators reported similar but not identical errors. For example, all identified a problem with the document language, but only some specified which key or attribute was missing or incorrect.

This comparison highlights the consistency and reliability of various PDF/UA validation tools and helps identify cases where validator interpretations may differ.

Additional Notes and Sources…

About the Comparison – Read more about PDF/UA-1 Accessibility Validator Comparison

Test Files – The sample PDF files used in this comparison can be downloaded from the official veraPDF corpus.

Reference Standards – The validation is based the PDF/UA-1 (ISO 14289-1) standard.

Validator Versions Used:

Meaning of “x”:

  • veraPDF = No problems found
  • Adobe Preflight PDF/UA = No problems found
  • PAC = The PDF/UA requirements checked by PAC are fulfilled
  • CommonLook PDF Validator = Total of Failed statuses: 0
Summary of PDF/UA Validation Outcomes…

Total files: 130

🟢 OK / agreement: 38 (29.2%)

🟠 Partial agreement: 25 (19.2%)

🔴 Different results: 67 (51.6%)

Table: PDF/UA-1 conformance issues detected by various validators for listed PDF files

PDF File

veraPDF

Adobe Preflight PDF/UA

PAC

CommonLook PDF Validator

5 Version identification

🟢 5-t01-fail-a

The document metadata stream doesn’t contain PDF/UA Identification Schema

PDF/UA identifier missing

PDF/UA identifier missing

The metadata stream in the Catalog dictionary does not include the PDF/UA identifier

🔴 5-t02-fail-a

The “part” property of the PDF/UA Identification Schema is 2 instead of 1 for PDF/UA-1 conforming file

The PDF/UA ‘part’ value is not 1

x

x

🔴 5-t03-fail-a

Property “part” of the PDF/UA Identification Schema has invalid namespace prefix pdfuaia

x

PDF/UA identifier missing

The metadata stream in the Catalog dictionary does not include the PDF/UA identifier

🔴 5-t04-fail-a

Property “amd” of the PDF/UA Identification Schema has invalid namespace prefix pdfuaia

PDF/UA ID: part entry missing

x

The metadata stream in the Catalog dictionary does not include the PDF/UA identifier

🔴 5-t05-fail-a

Property “corr” of the PDF/UA Identification Schema has invalid namespace prefix pdfuaia

PDF/UA ID: part entry missing

x

The metadata stream in the Catalog dictionary does not include the PDF/UA identifier

7.1 General

🔴 7.1-t01-fail-a

  • Content marked as Artifact is present inside tagged content
  • Tagged content should not be present inside content marked as Artifact

Content marked as Artifact is inside tagged content

Artifact present inside tagged content

  • Document does not define the dc:Title metedata attribute
  • An element of type Path may not have Span as a parent
  • A local link is not tagged within a link Reference

🔴 7.1-t02-fail-a

  • Content marked as Artifact is present inside tagged content
  • Tagged content should not be present inside content marked as Artifact

Tagged content present inside content marked as Artifact

Tagged Content present inside an artifact

  • Document does not define the dc:Title metedata attribute
  • A local link is not tagged within a link Reference

🔴 7.1-t03-fail-a

Content is neither marked as Artifact nor tagged as real content

Content neither Artifact nor tagged content

Image object not tagged

Document does not define any headings

🔴 7.1-t03-fail-b

Content is neither marked as Artifact nor tagged as real content

Content neither Artifact nor tagged content

Text object not tagged

Document does not define any headings

🟢 7.1-t04-fail-a

Suspects entry has a value of true

Suspects entry has a value of true

Suspects entry is set

The Suspects entry is set to true

🟢 7.1-t05-fail-a

Non-standard structure type is not mapped to a standard type

Element does not use standard tag

Non-standard structure type is neither mapped to a standard structure type nor to another non-standard structure type

  • The Standard tag is not a standard type and is not role-mapped.
  • A tag of type Standard shouldn’t be nested in Document

🟢 7.1-t05-fail-b

Non-standard structure type is not mapped to a standard type

Element does not use standard tag

Non-standard structure type is neither mapped to a standard structure type nor to another non-standard structure type

  • The Standard tag is not a standard type and is not role-mapped
  • The Text body tag is not a standard type and is not role-mapped
  • A tag of type Standard shouldn’t be nested in Document
  • A tag of type Text body shouldn’t be nested in Document

🟢 7.1-t05-fail-c

Non-standard structure type is not mapped to a standard type

Element does not use standard tag

Non-standard structure type is neither mapped to a standard structure type nor to another non-standard structure type

  • The Standard tag is not a standard type and is not role-mapped
  • A tag of type Standard shouldn’t be nested in Document

🔴 7.1-t05-fail-d

A circular mapping exists for Text body structure type

  • Circular mapping in role map
  • Element does not use standard tag

x crash

  • Role-map for the Standard custom tag is circular
  • Role-map for the Text body custom tag is circular
  • A tag of type Standard shouldn’t be nested in Document
  • Document does not define any headings

🟠 7.1-t06-fail-a

A circular mapping exists for structure type

Circular mapping in role map

  • The date is not a valid XMP date
  • Standard structure type is remapped
  • Structure type is remapped in a circular fashion

Document redefines the LI standard tag type

🟢 7.1-t07-fail-a

Standard type is remapped

Standard tag remapped to non-standard tag in role map

  • Standard structure type is remapped
  • Non-standard structure type is neither mapped to a standard structure type nor to another non-standard structure type

Document redefines the Document standard tag type.

🟠 7.1-t08-fail-a

The document catalog dictionary doesn’t contain metadata key or metadata stream dictionary does not contain either entry Type with value /Metadata or entry Subtype with value /XML

XMP Metadata entry missing

XMP metadata missing in document

  • The metadata stream in the Catalog dictionary does not include the PDF/UA identifier
  • Document does not define the dc:Title metedata attribute

🟢 7.1-t09-fail-a

Metadata stream does not contain dc:title

Metadata stream does not contain dc:title

Title missing in document’s XMP metadata

Document does not define the dc:Title metedata attribute.

🟢 7.1-t10-fail-a

ViewerPreferences dictionary is not present in the document Catalog, or DisplayDocTitle key is set to false or is not present in the ViewerPreferences dictionary

DisplayDocTitle entry missing or false

DisplayDocTitle entry is not set

ViewerPreferences dictionary of the Catalog dictionary does not contain DisplayDocTitle key.

🟢 7.1-t10-fail-b

ViewerPreferences dictionary is not present in the document Catalog, or DisplayDocTitle key is set to false or is not present in the ViewerPreferences dictionary

DisplayDocTitle entry missing or false

DisplayDocTitle entry is not set

Document does not set the Viewer Preferences to display the document title.

🔴 7.1-t11-fail-a

StructTreeRoot entry is not present in the document catalog

x

x

Document has no tags

7.2 Text

🟢 7.2-t02-fail-a

Natural language in the Outline entries cannot be determined

  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined

Natural language of a bookmark (outline item) cannot be determined

  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author

🔴 7.2-t03-fail-a

Table element contains P element(s) instead of TR, THead, TBode, TFoot or Caption

x

  • Invalid use of a P structure element
  • Invalid use of a TFoot structure element
  • A tag of type Table may not have P as a direct child
  • A tag of type P shouldn’t be nested in Table
  • Document does not define any headings

🔴 7.2-t03-fail-b

Table element contains 2 Caption elements instead of one

x

Invalid use of a Caption structure element

  • The tag Table contains 2 children of type Caption. The maximum allowed is 1
  • Document does not define any headings

🔴 7.2-t03-fail-c

Table element contains Caption as its 4 child instead of first or last one

x

Invalid use of a Caption structure element

Document does not define any headings

🔴 7.2-t04-fail-a

TR element contained in Document instead of Table, THead, TBody or TFoot element

x

Invalid use of a TR structure element

  • A tag of type TR may not have Document as a parent
  • A tag of type TR shouldn’t be nested in Document
  • Document does not define any headings

🔴 7.2-t05-fail-a

THead element contained in Document instead of Table element

x

Invalid use of a Head structure element

  • A tag of type THead may not have Document as a parent
  • A tag of type THead shouldn’t be nested in Document
  • Document does not define any headings

🔴 7.2-t06-fail-a

TBody element contained in Document instead of Table element

x

Invalid use of a TBody structure element

  • A tag of type TBody may not have Document as a parent
  • A tag of type TBody shouldn’t be nested in Document
  • Document does not define any headings

🔴 7.2-t07-fail-a

TFoot element contained in Document instead of Table element

x

Invalid use of a TFoot structure element

  • A tag of type TFoot may not have Document as a parent
  • A tag of type TFoot shouldn’t be nested in Document
  • Document does not define any headings

🔴 7.2-t08-fail-a

  • TH element contained in THead instead of TR element
  • THead element contains TH,TH element(s) instead of TR

x

Invalid use of a TH structure element

  • A tag of type TH may not have THead as a parent
  • A tag of type THead may not have TH as a direct child
  • A tag of type TH shouldn’t be nested in THead
  • Document does not define any headings.
  • Cell does not have column headers associated with it

🔴 7.2-t09-fail-a

  • TBody element contains TD,TD element(s) instead of TR
  • TD element contained in TBody instead of TR element

x

Invalid use of a TD structure element

  • A tag of type TD may not have TBody as a parent
  • A tag of type TBody may not have TD as a direct child
  • A tag of type TD shouldn’t be nested in TBody
  • Document does not define any headings

🔴 7.2-t10-fail-a

TR element contains Span element(s) instead of TH or TD

x

Invalid use of a Span structure element

  • A tag of type TR may not have Span as a direct child
  • A tag of type Span shouldn’t be nested in TR
  • Document does not define any headings

🟢 7.2-t11-fail-a

Table element contains more than one THead kid

More than one THead entry in table

Invalid use of a Head structure element

  • The tag Table contains 2 children of type THead. The maximum allowed is 1
  • Document does not define any headings

🟢 7.2-t12-fail-a

Table element contains more than one TFoot kid

More than one TFoot entry in table

Invalid use of a TFoot structure element

  • The tag Table contains 2 children of type TFoot. The maximum allowed is 1
  • Document does not define any headings.

🟢 7.2-t13-fail-a

Table element contains TFoot kid, but does not contain TBody kids

Table contains TFoot but no TBody

Invalid use of a TR structure element

  • A table containing THead or TFoot and does not contain any TBody elements has been detected.
  • Document does not define any headings.

🟢 7.2-t14-fail-a

Table element contains THead kid, but does not contain TBody kids

Table contains THead but no TBody

Invalid use of a TR structure element

  • A table containing THead or TFoot and does not contain any TBody elements has been detected.
  • Document does not define any headings.

🟢 7.2-t17-fail-a

LI element contained in Document instead of L element

No problems found

Invalid use of a LI structure element

  • A tag of type LI shouldn’t be nested in Document
  • Document does not define any headings
  • A tag of type LI may not have Document as a parent

🔴 7.2-t18-fail-a

LBody element contained in Document instead of LI element

x

Invalid use of a LBody structure element

  • A tag of type LBody shouldn’t be nested in Document
  • Document does not define any headings
  • A tag of type LBody may not have Document as a parent

🔴 7.2-t19-fail-a

L element contains Caption as its 5 child instead of first one

x

Invalid use of a Caption structure element

Document does not define any headings

🔴 7.2-t19-fail-b

L element contains Span element(s) instead of L, LI or Caption

x

Invalid use of a Span structure element

  • A tag of type Span shouldn’t be nested in L
  • Document does not define any headings
  • A tag of type L may not have Span as a direct child
  • The List contains no Lbl elements but the ListNumbering attribute is not set to None

🔴 7.2-t19-fail-c

L element contains Caption as its 6 child instead of first one

x

Invalid use of a Caption structure element

Document does not define any headings

🔴 7.2-t20-fail-a

LI element contains Span element(s) instead of Lbl or LBody

x

x

  • Document does not define any headings
  • Some List Items contain Lbl elements while others don’t
  • The List contains no Lbl elements but the ListNumbering attribute is not set to None

🔴 7.2-t20-fail-b

LI element contains Span element(s) instead of Lbl or LBody

x

x

Document does not define any headings

🟢 7.2-t21-fail-a

  • Natural language for text in ActualText attribute cannot be determined
  • Natural language for text in page content cannot be determined
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language of actual text cannot be determined
  • Natural language of a bookmark (outline item) cannot be determined
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Unable to determine the language for page content in tag
  • Unable to determine the language of the Actual Text attribute of the element

🟢 7.2-t22-fail-a

  • Natural language for text in Alt attribute cannot be determined
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language of alternative text cannot be determined
  • Natural language of alternative text cannot be determined
  • Natural language of a bookmark (outline item) cannot be determined
  • The highlighted Figure tag is missing the BBox attribute or is incorrect
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Unable to determine the language of the Alt attribute of the element
  • A tag of type Caption shouldn’t be nested in Figure

🟢 7.2-t23-fail-a

  • Natural language for text in E attribute cannot be determined
  • Natural language for text in page content shall be determined
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language for text object cannot be determined
  • Natural language of expansion text cannot be determined
  • Natural language of a bookmark (outline item) cannot be determined
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Unable to determine the language for page content in tag
  • Unable to determine the language of the Expansion Text attribute of the element

🟢 7.2-t24-fail-a

  • Natural language in the Contents entry for annotations cannot be determined
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language of a bookmark (outline item) cannot be determined
  • Natural language of a Contents entry cannot be determined
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Unable to determine the language of the Contents attribute of the element

🟠 7.2-t25-fail-a

  • Natural language in the Outline entries cannot be determined
  • Natural language in the TU key for form fields cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for form field’s tooltip undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language of a bookmark (outline item) cannot be determined
  • The Language of the bookmark can not be determined.
  • Unable to determine the language of the following Metadata entries: Title, Author

🔴 7.2-t26-fail-a

TOCI element contained in Document instead of TOC element

x

Invalid use of a TOCI structure element

  • A tag of type TOCI may not have NonStruct as a parent
  • A tag of type TOCI shouldn’t be nested in NonStruct
  • A tag of type Lbl shouldn’t be nested in Link
  • A tag of type Lbl may not have Link as a parent

🔴 7.2-t27-fail-a

TOC element contains Caption as its 5 child instead of first one

x

Invalid use of a Caption structure element

  • A tag of type TOCI may not have Text as a direct child
  • A tag of type TOC may not have TOC as a direct child
  • A tag of type TOC may not have Caption as a direct child
  • A tag of type TOC shouldn’t be nested in TOC
  • A tag of type Caption shouldn’t be nested in TOC
  • A tag of type Lbl shouldn’t be nested in Link
  • A tag of type Lbl may not have Link as a parent

🔴 7.2-t27-fail-b

TOC element contains Caption as its 5 child instead of first one

x

Invalid use of a Caption structure element

  • A tag of type TOC may not have Caption as a direct child
  • A tag of type TOC may not have TOC as a direct child
  • A tag of type Caption shouldn’t be nested in TOC
  • A tag of type TOC shouldn’t be nested in TOC
  • A tag of type Lbl shouldn’t be nested in Link
  • A tag of type Lbl may not have Link as a parent

🔴 7.2-t27-fail-c

TOC element contains P element(s) instead of TOC, TOCI or Caption

x

Invalid use of a P structure element

  • A tag of type TOC may not have Caption as a direct child
  • A tag of type TOC may not have P as a direct child
  • A tag of type TOC may not have TOC as a direct child
  • A tag of type Caption shouldn’t be nested in TOC
  • A tag of type P shouldn’t be nested in TOC
  • A tag of type TOC shouldn’t be nested in TOC
  • A tag of type Lbl shouldn’t be nested in Link
  • A tag of type Lbl may not have Link as a parent

🔴 7.2-t29-fail-a

🔴 7.2-t29-fail-b

🔴 7.2-t29-fail-c

Value portugues-pt of the Lang entry is not a Language-Tag

x

Document language metadata contains a syntax error

Document does not define any headings.

🟠 7.2-t29-fail-d

🟠 7.2-t29-fail-e
🟠 7.2-t29-fail-f

🟠 7.2-t29-fail-l

🟠 7.2-t29-fail-m

  • Value of the Lang entry is not a Language-Tag
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language of a bookmark (outline item) cannot be determined
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Document does not define any headings

🟠 7.2-t29-fail-g
🟠 7.2-t29-fail-h

🟠 7.2-t29-fail-i

🟠 7.2-t29-fail-o

🟠 7.2-t29-fail-p

  • Value of the Lang entry is not a Language-Tag
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language of a bookmark (outline item) cannot be determined
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Unable to determine the language for page content in tag
  • Document does not define any headings

🔴 7.2-t29-fail-j

🔴 7.2-t29-fail-k

Value of the Lang entry is not a Language-Tag

x

Document language metadata contains a syntax error

Document does not define any headings.

🟠 7.2-t29-fail-n

Value of the Lang entry is not a Language-Tag

  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined

Natural language of a bookmark

  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Document does not define any headings

🟠 7.2-t30-fail-a

  • Natural language for text in ActualText attribute in Span Marked Content cannot be determined
  • Natural language for text in page content cannot be determined
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language of a bookmark (outline item) cannot be determined
  • Natural language of actual text cannot be determined
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Unable to determine the language for page content in tag
  • Document does not define any headings

🟠 7.2-t31-fail-a

  • Natural language for text in Alt attribute in Span Marked Content cannot be determined
  • Natural language for text in page content cannot be determined
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language for text object cannot be determined
  • Natural language of alternative text object cannot be determined
  • Natural language of a bookmark (outline item) cannot be determined
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Unable to determine the language for page content in tag
  • Document does not define any headings

🟠 7.2-t32-fail-a

  • Natural language for text in E attribute in Span Marked Content cannot be determined
  • Natural language for text in page content cannot be determined
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language for text object cannot be determined
  • Natural language of expansion text object cannot be determined
  • Natural language of a bookmark (outline item) cannot be determined
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Unable to determine the language for page content in tag
  • Document does not define any headings

🟢 7.2-t33-fail-a

  • Natural language for document metadata cannot be determined
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language of a bookmark (outline item) cannot be determined
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Document does not define any headings

🟠 7.2-t34-fail-a

  • Natural language for text in page content cannot be determined
  • Natural language in the Outline entries cannot be determined
  • Natural language for bookmarks undefined
  • Natural language for document metadata undefined
  • Natural language for ActualText undefined
  • Natural language for Alt undefined
  • Natural language for E undefined
  • Document language metadata contains a syntax error
  • Natural language for text object cannot be determined
  • Natural language of a bookmark (outline item) cannot be determined
  • The Language of the bookmark can not be determined
  • Unable to determine the language of the following Metadata entries: Title, Author
  • Unable to determine the language for page content in tag

🔴 7.2-t36-fail-a

THead element contains Span element(s) instead of TR

x

  • Invalid use of a TR structure element
  • Invalid use of a Span structure element
  • A tag of type THead may not have Span as a direct child
  • A tag of type Span shouldn’t be nested in THead
  • Document does not define any headings

🔴 7.2-t37-fail-a

TBody element contains Span element(s) instead of TR

x

  • Invalid use of a TR structure element
  • Invalid use of a Span structure element
  • A tag of type TBody may not have Span as a direct child
  • A tag of type Span shouldn’t be nested in TBody
  • Document does not define any headings

🔴 7.2-t38-fail-a

TFoot element contains Span element(s) instead of TR

x

  • Invalid use of a TR structure element
  • Invalid use of a Span structure element
  • A tag of type TFoot may not have Span as a direct child
  • A tag of type Span shouldn’t be nested in TFoot
  • Document does not define any headings

🟢 7.2-t41-fail-a

Table rows 1 and 2 span different number of columns

  • Neither Scope nor Headers/IDs for TH cell
  • Table not evenly structured 
  • Irregular table row
  • Table header cell has no associated subcells
  • Document does not define any headings
  • Cell does not have column headers associated with it
  • Scope attribute not specified for TH element.

🔴 7.2-t42-fail-a

Table rows 1 and 2 span different number of columns

Table not evenly structured 

Irregular table row

Document does not define any headings

🔴 7.2-t43-fail-a

Table rows 1 and 2 span different number of columns (4 and 3 respectively)

Table not evenly structured

Irregular table row

Document does not define any headings

🔴 7.2-t43-fail-b

Table rows 1 and 2 span different number of columns (2 and 1 respectively)

Table not evenly structured

Irregular table row

x

🔴 7.2-t43-fail-c

Table rows 1 and 2 span different number of columns (5 and 1 respectively)

x

Irregular table row

x

7.3 Graphics

🟢 7.3-t01-fail-a

Figure structure element neither has an alternate description nor a replacement text

Neither Alt nor ActualText present for Figure

Alternative text missing for Figure structure element

A tag of type Figure does not define the Alt or Actual Text attributes.

🔴 7.3-t01-fail-b

Figure structure element neither has an alternate description nor a replacement text

Neither Alt nor ActualText present for Figure

Alternative text missing for Figure structure element

x

7.4 Headings

🟢 7.4.2-t01-fail-a

Heading level 1 is skipped in a descending sequence of header levels

First numbered heading not H1

First heading is not on the first level

Heading Level skipped. Previous heading level is 0, current Heading Level is 2.

🟢 7.4.2-t01-fail-b

Heading level 3 is skipped in a descending sequence of header levels

Heading level skipped

Numbered heading skips one or more heading levels

Heading Level skipped. Previous heading level is 2, current Heading Level is 4.

🔴 7.4.4-t01-fail-a

A node contains more than one H tag

x

More then one H structure element inside parent structure element

A node contains more than one H tag

🟢 7.4.4-t02-fail-a

Document uses both H and H# tags

Document uses both H and H1, H2, … tags

H and Hn structure elements found

  • Document uses both unnumbered and numbered heading tags
  • Document uses both unnumbered and numbered heading tags

🟢 7.4.4-t02-fail-b

Document uses both H and H# tags

Document uses both H and H1, H2, … tags

H and Hn structure elements found

Document uses both unnumbered and numbered heading tags

🟢 7.4.4-t03-fail-a

Document uses both H and H# tags

  • Document uses both H and H1, H2, … tags
  • First numbered heading not H1

H and Hn structure elements found

Document uses both unnumbered and numbered heading tags

🟢 7.4.4-t03-fail-b

Document uses both H and H# tags

  • Document uses both H and H1, H2, … tags
  • First numbered heading not H1

H and Hn structure elements found

Document uses both unnumbered and numbered heading tags

7.5 Tables

🟠 7.5-t01-fail-a

TD does not contain Headers attribute, and Headers for this table cell cannot be determined algorithmically

Neither Scope nor Headers/IDs for TH cell

  • x – One or mores check could not be completed. An internal error has occured
  • Table header cell has no associated subcells
  • Cell (2,2) does not have column headers associated with it
  • Scope attribute not specified for TH element

🔴 7.5-t01-fail-b

TD does not contain Headers attribute, and Headers for this table cell cannot be determined algorithmically

x

Table header cell has no associated subcells

  • Cell (2,2) does not have column headers associated with it
  • Scope attribute not specified for TH element

🟠 7.5-t02-fail-a

TD references undefined Header(s) 12345, and Headers for this table cell cannot be determined algorithmically

Neither Scope nor Headers/IDs for TH cell

x – One or mores check could not be completed. An internal error has occured

Table header cell has no associated subcells

  • Cell (2,2) does not have column headers associated with it
  • Scope attribute not specified for TH element

7.7 Mathematical expressions

🟢 7.7-t01-fail-a

Formula structure element neither has an alternate description nor a replacement text

No Alt attribute present for Formula

Alternative text missing for Formula structure element

  • The highlighted Formula tag is missing the BBox attribute or is incorrect
  • A tag of type Formula does not define the Alt or Actual Text attributes

🟢 7.7-t01-fail-b

Formula structure element neither has an alternate description nor a replacement text

No Alt attribute present for Formula

Alternative text missing for Formula structure element

The highlighted Formula tag is missing the BBox attribute or is incorrect

7.9 Notes and references

🟠 7.9-t01-fail-a

ID key of the Note tag is not present

Note without ID

ID missing in Note structure element

A local link is not tagged within a link Reference

🟠 7.9-t01-fail-b

ID key of the Note tag is not present

Note without ID

ID missing in Note structure element

A local link is not tagged within a link Reference

🟠 7.9-t02-fail-a

ID key note of the Note tag is non-unique

ID of Note not unique

ID entry in Note structure element is not unique

A local link is not tagged within a link Reference

7.10 Optional content

🔴 7.10-t01-fail-a

Missing or empty Name entry of the optional content configuration dictionary

OCCD name empty

x

  • Document does not define any headings
  • An Optional Content Configuration entry does not define the Name entry

🔴 7.10-t01-fail-b

Missing or empty Name entry of the optional content configuration dictionary

OCCD name missing

x

  • Document does not define any headings
  • An Optional Content Configuration entry does not define the Name entry

🟢 7.10-t02-fail-a

The AS key shall not appear in any optional content configuration dictionary

Optional content configuration dictionary has AS entry

OCCD (optional content configuration dictionary) contains AS key

  • Document does not define any headings
  • An Optional Content Configuration entry defines the AS key

7.11 Embedded files

🔴 7.11-t01-fail-a

The file specification dictionary for an embedded file does not contain either F or UF key or at least one of the keys is empty

Embedded file present but no F key

F or UF key missing in file specification

A local link is not tagged within a link Reference

🔴 7.11-t01-fail-b

The file specification dictionary for an embedded file does not contain either F or UF key or at least one of the keys is empty

Embedded file present but no UF key

F or UF key missing in file specification

A local link is not tagged within a link Reference

7.15 XFA

🔴 7.15-t01-fail-a

Dynamic XFA forms is present

PDF is dynamic XFA form

PDF contains a dynamic XFA form

This document is protected!

7.16 Security

🟢 7.16-t01-fail-a

The file is encrypted but does not contain a P entry in its encryption dictionary or the file is encrypted and does contain a P entry, but the 10th bit position of the P entry is false

  • Encrypted PDF disallows content extraction
  • The file is encrypted but does not contain a P entry in its encryption dictionary or the file is encrypted and does contain a P entry, but the 10th bit position of the P entry is false

Security settings block assistive technologies from acessing document’s content

This document is protected!

7.18 Annotations

🔴 7.18.1-t01-fail-a

Highlight annotation is an Artifact or is nested within H1 tag instead of Annot

x

Annotation is not nested inside anAnnot structure element

An element of type Annotation may not have H1 as a parent

🟢 7.18.1-t02-fail-a

Highlight annotation whose hidden flag is not set and whose rectangle is not outside the crop-box has neither Contents key nor an Alt entry in the enclosing structure element

Annotation lacks both Contents entry and Alt entry

Alternative description missing for an annotation

  • Document does not define any headings
  • An annotation doesn’t provide alternative text through the Contents key or Alt text of its parent tag

🔴 7.18.1-t02-fail-b

Highlight annotation whose hidden flag is not set and whose rectangle is not outside the crop-box has neither Contents key nor an Alt entry in the enclosing structure element

Annotation lacks both Contents entry and Alt entry

x

  • Document does not define any headings
  • An annotation doesn’t provide alternative text through the Contents key or Alt text of its parent tag

🔴 7.18.1-t02-fail-c

Highlight annotation whose hidden flag is not set and whose rectangle is not outside the crop-box has neither Contents key nor an Alt entry in the enclosing structure element

x

x

  • Document does not define any headings
  • An annotation doesn’t provide alternative text through the Contents key or Alt text of its parent tag

🔴 7.18.1-t03-fail-a

A form field neither has TU key nor its Widget annotations have alternative descriptions (in the form of an Alt entry in the enclosing structure element)

x

Alternate field name entry missing in form field “textfield”

The Form Annotation does not define the TU attribute.

🔴 7.18.1-t03-fail-b

A form field neither has TU key nor its Widget annotations have alternative descriptions (in the form of an Alt entry in the enclosing structure element)

x

x

The Form Annotation does not define the TU attribute.

🔴 7.18.1-t03-fail-c

A form field neither has TU key nor its Widget annotations have alternative descriptions (in the form of an Alt entry in the enclosing structure element)

x

Alternate field name entry missing in form field “textfield”

The Form Annotation does not define the TU attribute

🔴 7.18.1-t03-fail-d

A form field neither has TU key nor its Widget annotations have alternative descriptions (in the form of an Alt entry in the enclosing structure element)

x

Alternate field name entry missing in form field “butons”

  • Document does not define any headings
  • 2 Radio Buttons share the same variable name buttons. and hence would have the same tooltip (TU key)

🟢 7.18.2-t01-fail-a

An annotation of subtype TrapNet exists

Annotation of subtype TrapNet 

TrapNet annotation present

  • Document does not define any headings
  • A TrapNet annotation has been detected. TrapNet Annotations are not allowed in PDF/UA compliant files

🟢 7.18.3-t01-fail-a

A page with annotation(s) contains Tabs key with value null instead of S

  • Page contains annotations but no Tabs key
  • Page contains form fields but no Tabs key 

Tab order entry in page with annotations not set to S

Tab Order on page is not defined by the structure tree.

🟢 7.18.3-t01-fail-b

A page with annotation(s) contains Tabs key with value R instead of S

  • Page contains annotations but Tabs key not S 
  • Page contains form fields but Tabs key not S 

Tab order entry in page with annotations not set to S

Tab Order on page is not defined by the structure tree.

🔴 7.18.4-t01-fail-a

A Widget annotation is an Artifact or is nested within Document tag instead of Form

x

Widget annotation not nested inside a Form structure element

An element of type Annotation may not have Document as a parent

🔴 7.18.5-t01-fail-a

A Link annotation is an Artifact or is nested within P tag instead of Link

x

Link annotation is not nested inside a Link structure element

An element of type Annotation may not have P as a parent

🟠 7.18.5-t02-fail-a

  • Link annotation whose hidden flag is not set and whose rectangle is not outside the crop-box has neither Contents key nor an Alt entry in the enclosing structure element
  • A link annotation does not include an alternate description in the Contents key

Link without Contents entry 

Contents entry on an annotation exists, but is only comprised of whitespace

  • Parent tag of Link annotation doesn’t define the Alt attribute
  • Link Annotation doesn’t define the Contents attribute

🟠 7.18.5-t02-fail-b

  • Link annotation whose hidden flag is not set and whose rectangle is not outside the crop-box has neither Contents key nor an Alt entry in the enclosing structure element
  • A link annotation does not include an alternate description in the Contents key

Link without Contents entry 

Contents entry on an annotation exists, but is only comprised of whitespace

  • Parent tag of Link annotation doesn’t define the Alt attribute
  • Link Annotation doesn’t define the Contents attribute

🔴 7.18.6.2-t01-fail-a

CT key is missing from the media clip data dictionary

Media clip without CT entry

x

The highlighted Figure tag is missing the BBox attribute or is incorrect

🔴 7.18.6.2-t02-fail-a

Alt key (value null) is missing from the media clip data dictionary or has incorrect value

Media clip without Alt entry

x

The highlighted Figure tag is missing the BBox attribute or is incorrect

🔴 7.18.6.2-t02-fail-b

Alt key (value [, ]) is missing from the media clip data dictionary or has incorrect value

x

x

The highlighted Figure tag is missing the BBox attribute or is incorrect

🔴 7.18.7-t01-fail-a

The file specification dictionary for an embedded file does not contain either F or UF key or at least one of the keys is empty

Embedded file present but no F key 

F or UF key missing in file specification

  • A FileAttachment annotation is missing the F key in its File Specifications dictionary
  • A FileAttachment annotation is missing the Desc key in its File Specifications dictionary

🔴 7.18.7-t01-fail-b

The file specification dictionary for an embedded file does not contain either F or UF key or at least one of the keys is empty

Embedded file present but no F key 

F or UF key missing in file specification

  • A FileAttachment annotation is missing the UF key in its File Specifications dictionary
  • A FileAttachment annotation is missing the Desc key in its File Specifications dictionary

🔴 7.18.7-t01-fail-c

The file specification dictionary for an embedded file does not contain either F or UF key or at least one of the keys is empty

x

x

  • A FileAttachment annotation is missing the F key in its File Specifications dictionary
  • A FileAttachment annotation is missing the Desc key in its File Specifications dictionary

🔴 7.18.7-t01-fail-d

The file specification dictionary for an embedded file does not contain either F or UF key or at least one of the keys is empty

x

x

  • A FileAttachment annotation is missing the UF key in its File Specifications dictionary
  • A FileAttachment annotation is missing the Desc key in its File Specifications dictionary

🟢 7.18.8-t01-fail-a

A PrinterMark annotation is included in logical structure

PrinterMark annotation in logical structure 

PrinterMark annotation referenced by the logical structure

  • Document does not define any headings
  • A tagged PrinterMark annotation has been detected

7.20 XObjects

🟢 7.20-t01-fail-a

The document contains a reference XObject (Ref key in the form XObject dictionary)

Form XObject contains Ref key (referenced PDF)

Referenced external object present

  • Document does not define any headings
  • A Reference Form XObject has been detected. This object needs to be removed and replaced with content that doesn’t refer to content outside the document

🔴 7.20-t02-fail-a

Form XObject contains MCIDs and is referenced more than once

x

Inconsistent entry found – structural parent tree

  • The highlighted Figure element contains elements belonging to multiple pages and should not define the BBox attribute
  • Document does not define any headings

7.21 Fonts

in progress…

in progress…

in progress…

in progress…

in progress…

We invite feedback, corrections, and suggestions from the accessibility community, tool developers, and users who work with these validators in practice. If you notice additional cases where tools disagree, or if you have insights into how specific results should be interpreted, please share your observations.

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