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Version: 1.1

Validation checks

The Pdftools SDK performs multiple lexical, syntactic, and semantic checks when validating a PDF document according to an ISO standard or a corporate directive.

The table shows details of the validation checks performed according to the specification and conformance level.

PDFPDF/A-1PDF/A-2 & PDF/A-3Level ULevel A
Lexical checks
Structure of tokens such as keywords, names, numbers, strings etc.xxxxx
Structure of the cross-reference tablexxxxx
File positions in the trailer dictionary, cross reference table, etc.xxxxx
Whether a referenced object has the correct object and generation numberxxxxx
Length attribute of stream objectsxxxxx
No header offsetxxxx
Contains a binary markerxxxx
Syntactic checks
Structure of dictionaries, arrays, indirect objects, streams, etc.xxxxx
Compression errors, e.g. CCITT, JPEG, Flate, etc.xxxxx
Errors in embedded font programsxxxxx
Errors in ICC color profilesxxxxx
Semantic checks
Required entries in dictionaries, e.g. width entry in an image dictionaryxxxxx
Inherited attributesxxxxx
Value of the parent entries in dictionaries, e.g. page objectsxxxxx
Type of the dictionary entry's value, e.g. integer, string, namexxxxx
Whether the object must be indirect or direct, e.g. a page object must be an indirect objectxxxxx
Order of operators in content streamsxxxxx
Number of operands of the operatorsxxxxx
Type of operands of the operatorsxxxxx
Value ranges of the operandsxxxxx
Unknown referenced resourcesxxxxx
Operand stack overflow and underflowxxxxx
Inconsistent information, e.g. if an image has a stencil mask and soft mask at the same timexxxxx
Conformance to implementation limits defined by the PDF Referencexxxxx
No unredered XFA formsxxxxx
Contains a unique file identifierxxxx
Contains document metadataxxxx
Contains embedded font programs where neededxxxx
Contains character to glyph mapping (encoding) information for the fontsxxxx
Contains an output intent if neededxxxx
No encryptionxxxx
No LZW and non-standard filtersxxxx
No JavaScriptxxxx
No unallowed annotationsxxxx
No unallowed actionsxxxx
No form fields that are generated on the flyxxxx
No embedded PostScript codexxxx
No invisible, hidden or non-printable annotationsxxxx
No device-specific color spacesxxxx
No unknown rendering intentsxxxx
No image interpolationxxxx
No externally referenced information (external streams, reference XObjects, etc.)xxxx
No Open Print Interface (OPI) informationxxxx
No alternate imagesxxxx
No color transfer and half-toning functionsxxxx
No JPXxxxx
No layersxxxx
No transparencyxxxx
No embedded filesxxxx
No XRef streamsxxxx
Conformity of metadataxxxx
PDF/A conformance of embedded filesxxx
Consistency of spot colorsxxx
Contains Unicode information of fonts where neededxx
Contains logical structure information (tagging)x
Contains alternate descriptions of content (replacement text) where neededx