Adobe® Supplement toISO 32000-1
BaseVersion: 1.7
ExtensionLevel: 5

Adobe® Acrobat® SDK
Version 9.1
June 2009© 2009 Adobe Systems Incorporated. All rights reserved.
Adobe® Acrobat® 9.1 SDK Adobe Supplement to the ISO 32000
Edition 2.0, June 2009
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Adobe Extensions Level 5		Contents1Preface.............................................................................................................................................................42Transitioning the PDF Specification to ISO..............................................................................................53
3.1
3.2
3.3
3.4

Extensions to ISO 32000-1...........................................................................................................................7Transparency...........................................................................................................................................7Portable Collections...............................................................................................................................7Rich Text Strings.....................................................................................................................................8XFA...........................................................................................................................................................83

Adobe Extensions Level 5		41 Preface
The Portable Document Format (PDF) is a file format for representing documents in a manner independent of
the application software, hardware, and operating system used to create them and of the output device on which
they are to be displayed or printed.

What’s in this guide?
This document describes Adobe’s extension and implementation notes relative to the ISO 32000-1:2008, Document management, Portable document format, PDF 1.7. The extensions are to the PDF document format. Adobehas submitted these extensions to ISO for inclusion into the next version of the ISO 32000 specification and they
have all been accepted for part 2 of ISO 32000.

Who should read this guide?
This guide is intended for developers of applications that consume or produce PDF content.
Related documentation
The resources in this table can help you understand the material in this document. These documents, with theexception of ISO 32000, are available through the Adobe PDF Technology Center.
For information about
Adobe PDF specification
Adobe PDF specification for redaction annotations
Corrections to the PDF specification
ISO version of the PDF Reference.

Resource
PDF Reference, sixth edition, version 1.7
PDF Redaction: Addendum to the PDF Reference,
sixth edition, version 1.7
Errata for the PDF Reference, sixth edition, version 1.7
ISO 32000-1:2008

Adobe Extensions Level 5		

52 Transitioning the PDF Specification to ISO
Adobe has transferred responsibility for the PDF specification to the International Standards Organization(ISO) which has published ISO 32000, Document management, Portable document format, PDF 1.7 - otherwise
known as ISO 32000-1:2008. Consequently, this document normatively references that document..

Extensions to the PDF specification
The language extensions described in this guide have been submitted to ISO as proposed changes to the PDF
specification and the ISO 32000 committee has accept them for inclusion into part 2 of ISO 32000. The text inthis document reflects the exact syntax and semantics of the ISO versions as implemented in Acrobat & Reader
9.1 and later.
In the past, Adobe identified extensions to the PDF specification with PDF version identifiers, such as PDF 1.7.
Now that ISO has responsibility for the PDF specification, such identification is no longer within Adobe’s control. As an alternative, Adobe will use the extensions mechanisms defined for ISO 32000-1 by which Adobe andother companies can identify extensions to the PDF specification.
The new convention lets companies and other entities identify their own extensions relative to a base version ofPDF. Additionally, the convention identifies extension levels relative to that base version. For normative information on the use of base versions and extension levels in a PDF document, see ISO 32000-1:2008, 7.12.
Behavior of PDF consumers that does not support an extension
The extension convention also relies on the behavior of PDF consuming applications when they encounter PDF
properties they do not recognize. The Section 2.2.8 “Extensibility” in the PDF Reference, sixth edition, version
1.7 describes this behavior as follows:
PDF is designed to be extensible. Not only can new features be added, but applications based onearlier versions of PDF can behave reasonably when they encounter newer features that they do
not understand. Appendix H describes how a PDF consumer application should behave in suchcases.
And Appendix H in PDF Reference, sixth edition, version 1.7 provides this additional guidance:
Both viewer applications and PDF have been designed to enable users to view everything in thedocument that the viewer application understands and to ignore or inform the user about objects
not understood. The decision whether to ignore or inform the user is made on a feature-by-feature basis.
Subsequent extensions to a BaseVersion
Each subsequent company-specific extension level for a particular PDF base version is cumulative. In otherwords, PDF-processing applications that support the third extension level for a particular base level shall also
support the first and second extension levels.
It is Adobe’s intent to increment the base version extensions only with major releases of its PDF-processing applications. This document reflects that by documenting those extensions from Acrobat 9.1.

Adobe Extensions Level 5		

6Plans related to the first version of ISO 32000
The first version of ISO 32000 conveys exactly the same requirements as the PDF Reference, sixth edition, version 1.7 but made normative through the proper usage of ISO terminology. Because of this similarity and toavoid unnecessary confusion, Adobe will continue using 1.7 as its base version until the second release of ISO32000.
For information about changes Adobe made to PDF Reference, sixth edition, version 1.7 to become the ISO
Draft International Standard (DIS), see ISO 32000 — Summary of Changes. This document is available throughhttp://www.adobe.com/go/pdf_developer (select “PDF Specification, Sixth Edition”).

Plans related to subsequent versions of ISO 32000
After the second version of ISO 32000 is released, Adobe will use a new base version value that reflects the newVersion value specified by that second version of ISO 32000. Features that are included in the second ISO version will henceforth be considered as features of the ISO version and the designation (in the PDF files) as being
Adobe extensions will no longer be used.
Extensions described for the 1.7 base version that are incorporated into the second version of ISO 32000 will not
be included in future versions of this document. Extensions described in a prior release that are not incorporated
into ISO 32000 will remain in this document with their original base version and extension level.
The third and subsequent releases of ISO 32000 will repeat this pattern.

Adobe Extensions Level 5		

73 Extensions to ISO 32000-1
3.1 Transparency
The following material amends Section 11.3.5, “Blend Mode.”
NAME
ColorDodge

ColorBurn

TABLE 136 Standard separable blend modes
RESULT
Brightens the backdrop color to reflect the source
color. Painting with black produces no changes.
0,1,𝐵𝐵𝐵𝐵(𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 , 𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠 ) = �)�,�𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 /(1 − 𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠

𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 = 0
𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 ≥ (1 − 𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠 )𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑠𝑠𝑠𝑠𝑒𝑒𝑒𝑒

Darkens the backdrop color to reflect the source color.
Painting with white produces no change.
1,0,𝐵𝐵𝐵𝐵(𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 , 𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠 ) = �
1 − �(1 − 𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 )/𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠 �,𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 = 1(1 − 𝑐𝑐𝑐𝑐𝑏𝑏𝑏𝑏 ) ≥ 𝑐𝑐𝑐𝑐𝑠𝑠𝑠𝑠
𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑠𝑠𝑠𝑠𝑒𝑒𝑒𝑒

Note: These functions are formulated in a different way here than they are in ISO 32000-1. However, they produce the same results except in onespecial edge case. For ColorDodge, the special case is cb = 0 and cs = 1, where the result is now 0 instead of 1. For ColorBurn, the special caseis cb = 1 and cs = 0, where the result is now 1 instead of 0. The rationale for the change is that for any given cb, the result should be a continuousfunction of cs.

3.2 Portable Collections
3.2.1 Background
This proposal clarifies the behavior of the D entry when its value does not match any embedded file. ISO 32000-1
currently says that if the D entry “is missing or in error”, the root document should be shown. In retrospect, thesecond half of this definition was probably a mistake: if the D entry exists but doesn’t match a file, the most likely
explanation is that it did match a file at one time, but the file was removed. In that case it would be more desirable to select another file in the list than to show the root document, particularly when the root document has acompatibility message that advises the user to upgrade to the product they are currently using.
3.2.2 Proposal
In table 155 (12.3.5), the definition of the D key is amended as follows, with the new language underlined.

Adobe Extensions Level 5		

8Table 155 - Entries in a Collections dictionary
TYPE
VALUE
byte string(Optional) A string that identifies an entry in theEmbeddedFiles name tree, controlling the documentthat is initially presented in the user interface. If theD entry is missing or in error, the initial document is
the one that contains the collection dictionary. If theD entry is a valid byte string that does not match any
file in the EmbeddedFiles name tree, the conforminginteractive reader shall select the first item from thelist of files to display in its user interface; if no files exist in the name tree, the conforming interactive reader
shall display an empty preview window.

KEYD

3.3 Rich Text Strings
3.3.1 BackgroundISO 32000-1 currently supports a subset of XHTML for use in “Rich Text Strings” (12.7.3.4) for both annotations and form fields. A common use for such a field is to incorporate links (either entered by the author or by
a future editor), but while such links may be specified by URI, the links are not treated as active. This proposal
enables the standard <a> elements of XHTML to enable proper linking.
3.3.2 Proposal
The following material amends Section 12.7.3.4, “Rich Text Strings.”
Element<a>Element<href>

Table 223 - Updates to XHTML elements used in rich text string
Description
An anchor, or hyperlink reference, to an arbitrary URI

Table 224a - Attributes of the <a> element
Description
An arbitrary URI to which to link.
No syntax restrictions are placed on the value of the href attribute. A conforming reader can choose what types of URIs to support and how to handle
badly formed link targets or targets in unsupported syntax.
In addition, named anchors are not supported.

3.4 XFA
Adobe has update the XFA (XML Forms Architecture) technology to version 3.0 and the advancements there
have been implemented in Acrobat and Reader 9.1, and is recommended as the new normative reference for
XFA in PDF (ISO 32000-1:2008, 12.7.8). The documentation can be found at http://partners.adobe.com/public/developer/xml/index_arch.html.