PDF Tags

PDF Tags

The tags listed in the PDF tables below are those which are used by ExifTool to extract meta information, but they are only a small fraction of the total number of available PDF tags. See for the official PDF specification.

ExifTool supports reading and writing PDF documents up to version 1.7 extension level 3, including support for RC4, AES-128 and AES-256 encryption. A option is provided to allow processing of password-protected PDF files.

ExifTool may be used to write native PDF and XMP metadata to PDF files. It uses an incremental update technique that has the advantages of being both fast and reversible. If ExifTool was used to modify a PDF file, the original may be recovered by deleting the PDF-update pseudo-group (with -PDF-update:all= on the command line). However, there are two main disadvantages to this technique:

1) A linearized PDF file is no longer linearized after the update, so it must be subsequently re-linearized if this is required.

2) All metadata edits are reversible. While this would normally be considered an advantage, it is a potential security problem because old information is never actually deleted from the file. (However, after running ExifTool the old information may be removed permanently using the "qpdf" utility with this command: "qpdf --linearize in.pdf out.pdf".)

Tag ID Tag Name Writable Values / Notes
'Encrypt' Encrypt - -->
'Info' Info - -->
'Root' Root - -->
'_linearized' Linearized no (flag set if document is linearized for fast web display; not a real Tag ID)
'false' = No
'true' = Yes

Tags extracted from the document Encrypt dictionary.

Tag ID Tag Name Writable Values / Notes
'Filter' Encryption no (extracted value is actually a combination of the Filter, SubFilter, V, R and Length information from the Encrypt dictionary)
'P' UserAccess no
Bit 2 = Print
Bit 3 = Modify
Bit 4 = Copy
Bit 5 = Annotate
   Bit 8 = Fill forms
Bit 9 = Extract
Bit 10 = Assemble
Bit 11 = Print high-res

As well as the tags listed below, the PDF specification allows for user-defined tags to exist in the Info dictionary. These tags, which should have corresponding XMP-pdfx entries in the XMP of the PDF XML Metadata object, are also extracted by ExifTool.

Writable specifies the value format, and may be string, date, integer, real, boolean or name for PDF tags.

Tag ID Tag Name Writable Values / Notes
'AAPL:Keywords' AppleKeywords string+ (keywords written by Apple utilities, although they seem to use PDF:Keywords when reading)
'Author' Author string  
'CreationDate' CreateDate date  
'Creator' Creator string  
'Keywords' Keywords string+  
'ModDate' ModifyDate date  
'Producer' Producer string  
'Subject' Subject string  
'Title' Title string  
'Trapped' Trapped string!  

This is the PDF document catalog.

Tag ID Tag Name Writable Values / Notes
'AcroForm' AcroForm - -->
'Lang' Language no  
'MarkInfo' MarkInfo - -->
'Metadata' Metadata - -->
'PageLayout' PageLayout no  
'PageMode' PageMode no  
'Pages' Pages - -->
'Perms' Perms - -->
'Version' PDFVersion no  

Tag ID Tag Name Writable Values / Notes
'_has_xfa' HasXFA no (this tag is defined if a document contains form fields, and is true if it uses XML Forms Architecture; not a real Tag ID)
'false' = No
'true' = Yes

Tag ID Tag Name Writable Values / Notes
'Marked' TaggedPDF no (not a Tagged PDF if this tag is missing)
'false' = No
'true' = Yes

Tag ID Tag Name Writable Values / Notes
'XML_stream' XMP - -->

Tag ID Tag Name Writable Values / Notes
'Count' PageCount no  
'Kids' Kids - -->

Tag ID Tag Name Writable Values / Notes
'Kids' Kids - -->
'Metadata' Metadata - -->
'PieceInfo' PieceInfo - -->
'Resources' Resources - -->

Tag ID Tag Name Writable Values / Notes
'AdobePhotoshop' AdobePhotoshop - -->
'Illustrator' Illustrator - -->

Tag ID Tag Name Writable Values / Notes
'Private' Private - -->

Tag ID Tag Name Writable Values / Notes
'ImageResources' ImageResources - -->

Tag ID Tag Name Writable Values / Notes
'_stream' _stream - -->

Tag ID Tag Name Writable Values / Notes
'Private' Private - -->

Tag ID Tag Name Writable Values / Notes
'AIMetaData' AIMetaData - -->
'AIPDFPrivateData' AIPDFPrivateData - -->
'AIPrivateData' AIPrivateData - -->
(the option enables information to be extracted from embedded PostScript documents in the AIPrivateData# and AIPDFPrivateData# streams)
'ContainerVersion' ContainerVersion no  
'CreatorVersion' CreatorVersion no  
'RoundTripVersion' RoundTripVersion no  

Tag ID Tag Name Writable Values / Notes
'_stream' _stream - -->

Tag ID Tag Name Writable Values / Notes
'ColorSpace' ColorSpace - -->
'Properties' Properties - -->
'XObject' XObject - -->

Tag ID Tag Name Writable Values / Notes
'Cs1' Cs1 - -->
'DefaultCMYK' DefaultCMYK - -->
'DefaultRGB' DefaultRGB - -->

Tag ID Tag Name Writable Values / Notes
'_stream' _stream - -->

Tag ID Tag Name Writable Values / Notes
'ICCBased' ICCBased - -->

Tag ID Tag Name Writable Values / Notes
'_stream' _stream - -->

Tag ID Tag Name Writable Values / Notes
'MC' MC - -->
(the option enables information to be extracted from these embedded metadata dictionaries)

Tag ID Tag Name Writable Values / Notes
'Metadata' Metadata - -->

Tag ID Tag Name Writable Values / Notes
'Im' Im - -->
(the option enables information to be extracted from these embedded images)

Information extracted from embedded images with the option. The EmbeddedImage and its metadata are extracted only for JPEG and Jpeg2000 image formats.

Tag ID Tag Name Writable Values / Notes
'ColorSpace' EmbeddedImageColorSpace no+  
'Filter' EmbeddedImageFilter no+  
' ' EmbeddedImage no  
'Image_stream' EmbeddedImage no  
' ' EmbeddedImage no  

Additional document permissions imposed by digital signatures.

Tag ID Tag Name Writable Values / Notes
'DocMDP' DocMDP - -->
'FieldMDP' FieldMDP - -->
'UR3' UR3 - -->

Tag ID Tag Name Writable Values / Notes
'ContactInfo' SignerContactInfo no  
'Location' SigningLocation no  
'M' SigningDate no  
'Name' SigningAuthority no  
'Prop_AuthTime' AuthenticationTime no  
'Prop_AuthType' AuthenticationType no  
'Reason' SigningReason no  
'Reference' Reference - -->

Tag ID Tag Name Writable Values / Notes
'TransformParams' TransformParams - -->

Tag ID Tag Name Writable Values / Notes
'Action' FieldPermissions no (FieldMDP signatures only)
'All' = Disallow changes to all form fields
'Exclude' = Allow changes to specified form fields
'Include' = Disallow changes to specified form fields
'Annots' AnnotationUsageRights no+ (possible values are Create, Delete, Modify, Copy, Import and Export; additional values for UR3 signatures are Online and SummaryView)
'Document' DocumentUsageRights no+ (only possible value is FullSave)
'EF' EmbeddedFileUsageRights no+ (possible values are Create, Delete, Modify and Import)
'Fields' FormFields no+ (FieldMDP signatures only)
'Form' FormUsageRights no+ (possible values are FillIn, Import, Export, SubmitStandalone and SpawnTemplate; additional values for UR3 signatures are BarcodePlain and Online)
'FormEX' FormExtraUsageRights no+ (UR signatures only; only possible value is BarcodePlain )
'Msg' UsageRightsMessage no  
'P' ModificationPermissions no (1-3 for DocMDP signatures, default 2; true/false for UR3 signatures, default false)
1 = No changes permitted
2 = Fill forms, Create page templates, Sign
3 = Fill forms, Create page templates, Sign, Create/Delete/Edit annotations
'false' = Do not restrict applications to reader permissions
'true' = Restrict all applications to reader permissions
'Signature' SignatureUsageRights no+ (only possible value is Modify)

(This document generated automatically by Image::ExifTool::BuildTagLookup)
Last revised Sep 26, 2019