## 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 http://www.adobe.com/devnet/pdf/pdf_reference.html 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 Password option is provided to allow processing of password-protected PDF files.

When writing PDF files, ExifTool uses an incremental update. This has the advantages of being fast and reversible. The original PDF can be easily recovered by deleting the `PDF-update` pseudo-group (with `-PDF-update:all=` on the command line). But 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.

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

## PDF Encrypt Tags

Tags extracted from the document Encrypt dictionary.

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'Filter' | Encryption | N |
> 'P' | UserAccess | N |
> 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 |

## PDF Info Tags

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! |

## PDF Root Tags

This is the PDF document catalog.

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'Lang' | Language | N |
> 'MarkInfo' | MarkInfo | - | --> PDF MarkInfo Tags
> 'Metadata' | Metadata | - | --> PDF Metadata Tags
> 'PageLayout' | PageLayout | N |
> 'PageMode' | PageMode | N |
> 'Pages' | Pages | - | --> PDF Pages Tags
> 'Perms' | Perms | - | --> PDF Perms Tags
> 'Version' | PDFVersion | N |

## PDF MarkInfo Tags

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

## PDF Metadata Tags

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

## PDF Pages Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'Count' | PageCount | N |
> 'Kids' | Kids | - | --> PDF Kids Tags

## PDF Kids Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'Metadata' | Metadata | - | --> PDF Metadata Tags
> 'PieceInfo' | PieceInfo | - | --> PDF PieceInfo Tags
> 'Resources' | Resources | - | --> PDF Resources Tags

## PDF PieceInfo Tags

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

## PDF AdobePhotoshop Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'Private' | Private | - | --> PDF Private Tags

## PDF Private Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'ImageResources' | ImageResources | - | --> PDF ImageResources Tags

## PDF ImageResources Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> '_stream' | _stream | - | --> Photoshop Tags

## PDF Illustrator Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'Private' | Private | - | --> PDF AIPrivate Tags

## PDF AIPrivate Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'AIMetaData' | AIMetaData | - | --> PDF AIMetaData Tags
> 'AIPrivateData' | AIPrivateData | - | --> PostScript Tags (the ExtractEmbedded option enables information to be extracted from embedded PostScript documents in the AIPrivateData stream)
> 'ContainerVersion' | ContainerVersion | N |
> 'CreatorVersion' | CreatorVersion | N |
> 'RoundTripVersion' | RoundTripVersion | N |

## PDF AIMetaData Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> '_stream' | _stream | - | --> PostScript Tags

## PDF Resources Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'ColorSpace' | ColorSpace | - | --> PDF ColorSpace Tags

## PDF ColorSpace Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'DefaultRGB' | DefaultRGB | - | --> PDF DefaultRGB Tags

## PDF DefaultRGB Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'ICCBased' | ICCBased | - | --> PDF ICCBased Tags

## PDF ICCBased Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> '_stream' | _stream | - | --> ICC_Profile Tags

## PDF Perms Tags

Additional document permissions imposed by digital signatures.

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'DocMDP' | DocMDP | - | --> PDF Signature Tags
> 'FieldMDP' | FieldMDP | - | --> PDF Signature Tags
> 'UR3' | UR3 | - | --> PDF Signature Tags

## PDF Signature Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'ContactInfo' | SignerContactInfo | N |
> 'Location' | SigningLocation | N |
> 'M' | SigningDate | N |
> 'Name' | SigningAuthority | N |
> 'Prop_AuthTime' | AuthenticationTime | N |
> 'Prop_AuthType' | AuthenticationType | N |
> 'Reason' | SigningReason | N |
> 'Reference' | Reference | - | --> PDF Reference Tags

## PDF Reference Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'TransformParams' | TransformParams | - | --> PDF TransformParams Tags

## PDF TransformParams Tags

> Tag ID | Tag Name | Writable | Values / Notes
> --- | --- | --- | ---
> 'Action' | FieldPermissions | N | (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 | N+ | (UR3 signatures only)
> 'Document' | DocumentUsageRights | N+ | (UR3 signatures only)
> 'EF' | EmbeddedFileUsageRights | N+ | (UR3 signatures only)
> 'Fields' | FormFields | N+ | (FieldMDP signatures only)
> 'Form' | FormUsageRights | N+ | (UR3 signatures only)
> 'Msg' | UsageRightsMessage | N | (UR3 signatures only)
> 'P' | ModificationPermissions | N | (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 al applications to reader permissions
> 'Signature' | SignatureUsageRights | N+ | (UR3 signatures only)

(This document generated automatically by Image::ExifTool::BuildTagLookup)
Last revised Nov 19, 2010

<-- ExifTool Tag Names