SIST ISO 16612-2:2011

INTERNATIONAL ISO
STANDARD 16612-2
First edition
2010-08-15
Graphic technology — Variable data
exchange —
Part 2:
Using PDF/X-4 and PDF/X-5
(PDF/VT-1 and PDF/VT-2)
Technologie graphique — Échange de données d'impression
variables —
Partie 2: Utilisation de PDF/X-4 et PDF/X-5 (PDF/VT-1 et PDF/VT-2)

Reference number
©
ISO 2010
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ii © ISO 2010 – All rights reserved

Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms, definitions and abbreviated terms.2
3.1 Terms and definitions .2
3.2 Abbreviated terms .5
4 Notations .5
5 Conforming files and equipment .5
5.1 General .5
5.2 PDF/VT-1 conformance.6
5.3 PDF/VT-2 conformance.6
5.4 PDF/VT-2s conformance.6
5.5 All PDF/VT file conformance levels .6
5.6 Validation of PDF/VT files.6
6 Technical requirements .7
6.1 General .7
6.2 PDF/VT file requirements.7
6.3 PDF/VT-1 and PDF/VT-2 file identification .7
6.4 Architecture .8
6.5 Document part hierarchy.9
6.6 Document part metadata (DPM).11
6.7 Recurring graphical object definitions.12
Annex A (normative) Use of multipart MIME for streamed generation of PDF/VT data.16
Annex B (informative) PDF/X conformance summary.18
Annex C (informative) Example DPart structure.19
Annex D (normative) XML representation of the document part hierarchy.26
Annex E (normative) Naming conventions for DPM keys .31
Annex F (normative) Determining XObject equivalence.32
Bibliography.36

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 16612-2 was prepared by Technical Committee ISO/TC 130, Graphic technology.
ISO 16612 consists of the following parts, under the general title Graphic technology — Variable data
exchange:
⎯ Part 1: Using PPML 2.1 and PDF 1.4 (PPML/VDX-2005)
⎯ Part 2: Using PDF/X-4 and PDF/X-5 (PDF/VT-1 and PDF/VT-2)
iv © ISO 2010 – All rights reserved

Introduction
This part of ISO 16612 defines the PDF/VT document format which specifies methods for the use of the
Portable Document Format (PDF) for the definition and exchange of all content elements and supporting
metadata necessary for printing tasks involving variable or transactional document content. It allows the
specification of document structure, document layout, content data, and interaction of graphical elements in a
graphics model that supports transparency.
PDF/VT is designed to enable variable document printing (VDP) in a variety of environments from desktop
printers to digital production presses. This includes hybrid workflows involving both conventional and digital
printing.
This part of ISO 16612 defines three conformance levels as follows.
⎯ PDF/VT-1 for a complete single-file exchange. PDF/VT-1 requires all resources necessary for proper
interpretation of the PDF data to be included within the conforming PDF file.
⎯ PDF/VT-2 for multi-file exchange. PDF/VT-2 enables a conforming file to refer to an external ICC profile
file and additional content defined in external PDF/X conforming files for use as page content.
⎯ PDF/VT-2s for streamed delivery. PDF/VT-2s allows for processing (streaming) of multiple compound
entities representing graphical content before the entire PDF/VT instance has been generated. A
PDF/VT-2s stream is a MIME package that contains a sequence of one or more PDF/VT files and
supporting resources.
The present trend towards the separation of variable document content creation from the details of print
production workflow and printing device dependencies is evolving rapidly. The job definition format (JDF) job
ticket specification being developed by the International Cooperation for the Integration of Processes in
Prepress, Press, and Postpress Organization (CIP4) provides one means of specifying a print product and
corresponding production process in a way that is independent of any particular graphical content format.
PDF/VT is intended to be workflow-architecture-neutral. PDF/VT has no provision for encoding workflow or
device-specific control information. The aspects of device control, resource, and production management are
outside the scope of this part of ISO 16612. In a production environment, PDF/VT relies on the use of JDF, or
similar job ticket formats, to define a print product and the corresponding production requirements. The
primary focus of PDF/VT is on the exchange of content between businesses or within an integrated
environment that produces variable document printing.
Graphics design applications continue to evolve with greater capability and increased sophistication of the
graphical content and design effects based on a graphics model that supports transparency. This graphics
model is required to support features such as drop shadows and colour blending effects that are associated
with the interaction of transparent content objects. These capabilities are used in the creation of one-to-one
customer communication print applications including direct marketing documents, transactional documents,
and trans-promotional documents.
This part of ISO 16612, referred to as PDF/VT, includes support for the PDF 1.6 imaging model which
includes support for transparency. It builds on the PDF/X-4 and PDF/X-5 standards (defined in ISO 15930-7
and ISO 15930-8), which, in turn, reference PDF 1.6. Like ISO 16612-1, this part of ISO 16612 guarantees
portability of conforming VDP content and metadata across conforming digital printing systems. It is focused
on defining the content data and metadata necessary to support efficient workflow manipulation and
processing based on the use of JDF or similar job ticket formats. More specifically, the job ticket is expected to
define the production requirements and draw upon PDF/VT for its content and metadata resources.
This approach supports the fundamental requirements of portability, device and workflow independence and
guaranteed communication of the intended colour reproduction. The native constructs within PDF allow
products to provide functionality equivalent to that of PPML workflows as used in ISO 16612-1. This part of
ISO 16612 uses a single homogeneous format while adding support for a graphics model that supports
transparency, including support for interacting transparent objects.
This part of ISO 16612 is based on PDF/X-4 and PDF/X-5 allowing users to continue to use, and solution
vendors to build on, existing PDF-based workflow tools and job-ticket-based VDP workflow architecture similar
to PPML/VDX, with the added capability of the full graphics model of PDF 1.6.
PDF/VT supports the use of graphical object definitions as a method of specifying graphical content data only
once in a PDF/VT file independent of the number of times it is referenced in the file. This approach serves to
reduce the file size of a PDF/VT instance and allows implementers of conforming readers to employ various
processing optimization strategies. Within the context of PDF/X-4, these graphical objects are specified as
image, form and transparency group XObjects. Use of PDF/X-5g and PDF/X-5pg allows for the use of
reference XObjects where the XObject's content stream is that of a page of a referenced PDF file.
While strongly recommended, there is nothing in this part of ISO 16612 that enforces the creation of PDF/VT
files that make efficient use of XObjects.
XObjects referenced multiple times from various content streams can be tagged with hint information that aids
the conforming reader in its determination of XObject reuse. These hints include an explicit lifetime scope to
indicate the context within which the XObject is known to be referenced multiple times, such as within the
current file, across multiple files of a PDF/VT instance or across PDF/VT instances. An XObject can also be
tagged with an identifier to assist a conforming reader in the identification and management of such recurring
definitions, such as in the case where it is known to occur across multiple PDF/VT files.
An XObject can also be identified as an encapsulated XObject if its definition has a limited and well-defined
interaction with the current graphic state when invoked. This explicit hint serves to assist a conforming reader
in its optimization strategy.
This part of ISO 16612 enables an exchange of content where no additional technical information is required
to be communicated between sender and receiver for the purpose of describing the appearance of page
content.
Application notes for this part of ISO 16612 are available to provide assistance to developers and users of
applications designed to conform to this part of ISO 16612 and can be found at
http://www.npes.org/Standards/toolspdfvt.html.
A reader conforming to this part of ISO 16612 is not required to support documents conforming to ISO 16612-1,
which is based on the use of PDF and PPML.
vi © ISO 2010 – All rights reserved

INTERNATIONAL STANDARD ISO 16612-2:2010(E)

Graphic technology — Variable data exchange —
Part 2:
Using PDF/X-4 and PDF/X-5 (PDF/VT-1 and PDF/VT-2)
1 Scope
This part of ISO 16612 defines the PDF/VT document format and methods to enable reliable document
exchange for variable data and transactional (VT) printing. It uses the Portable Document Format (PDF)
Version 1.6, as restricted by PDF/X-4 and PDF/X-5, for the representation of such documents. It allows the
specification of document structure and layout, content data, and interaction of graphical objects in a graphics
model that supports transparency and both device-dependent and device-independent colour spaces. All
elements are either included or provision is made for unique identification of externally supplied graphical
content or ICC profiles.
PDF/VT is designed to enable variable data and transactional printing in a variety of environments from
desktop printers to digital production presses. This includes hybrid workflows involving both conventional and
digital printing.
This part of ISO 16612 does not provide for the specification and encoding of production and device control
information but is constructed to enable its use with the CIP4 Job Document Format (JDF) or similar job ticket
formats.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 15930-7, Graphic technology — Prepress digital data exchange using PDF — Part 7: Complete exchange
of printing data (PDF/X-4) and partial exchange of printing data with external profile reference (PDF/X-4p)
using PDF 1.6
ISO 15930-8, Graphic technology — Prepress digital data exchange using PDF — Part 8: Partial exchange of
printing data using PDF 1.6 (PDF/X-5)
Adobe PDF Reference, fifth edition, version 1.6., Adobe Systems Incorporated (ISBN 0-321-30474-8).
Available from
Errata for the PDF Reference, fifth edition, version 1.6 dated 4 October 2006, Adobe Systems Incorporated.
Available from
Extensible Markup Language (XML) 1.0 (Second Edition), 6 October 2000, World Wide Web Consortium,
Available from
PDF Blend Modes: Addendum, 23 January 2006, Adobe Systems Incorporated. Available from

RFC 2045, Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies,
November 1996. Available from
RFC 2046, Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types, November 1996. Available
from
RFC 2047, MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for
Non-ASCII Text, November 1996. Available from
RFC 2183, Communicating Presentation Information in Internet Messages: The Content-Disposition Header
Field, August 1997. Available from
RFC 4122, A Universally Unique IDentifier (UUID) URN Namespace, July 2005. Available from

XML Path Language (XPath), version 1.0, WC3 Recommendation, 16 November 1999. Available from

3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
compound entity
unit of work with all text, graphics and image elements prepared for final print reproduction and that might
represent a single page for printing, a portion of a page or a combination of pages
3.1.2
document
collection of related document parts
NOTE A document part can also be a document.
3.1.3
document part
set of related pages or related sets of pages, or both
EXAMPLE Chapter pages of a book or all sets of pages intended for a recipient.
3.1.4
document part hierarchy
hierarchical data structure that specifies the organization of document parts
3.1.5
document part metadata
DPM
metadata associated with a document part
3.1.6
editor
application that is both a reader and a writer capable of modifying a file
3.1.7
encapsulated XObject
XObject having a well-defined limited interaction with the current graphics state at the point of invocation
2 © ISO 2010 – All rights reserved

3.1.8
environment context
set of reusable content
3.1.9
graphical object
graphical content definition comprising text, vector graphics, image data or some combination thereof
3.1.10
ICC
International Color Consortium
industry association formed to develop standardized mechanisms for colour management
3.1.11
ICC profile
set of colorimetric transforms prepared in accordance with ICC.1 or ISO 15076-1
3.1.12
interactive reader
reader that requires or allows human interaction with the content and other objects contained in the document
during the software's processing phase
NOTE A file viewing tool is an example of an interactive reader; a raster image processor is an example of a reader
that is not interactive.
[ISO 19005-1:2005]
3.1.13
job definition
information that specifies the production requirements and workflow of a unit of work involving purposing
PDF/VT content to one or more messaging channels
3.1.14
job ticket
electronic specification of print product or process control for print production, or both
3.1.15
PDF
Portable Document Format
file format defined in the PDF Reference
3.1.16
PDF/VT
document format and methods to enable reliable document exchange for variable data and transactional
printing
3.1.17
PDF/VT chunk
conforming PDF/VT-1 file or PDF/VT-2 file set that is a member of a PDF/VT-2s stream
3.1.18
PDF/VT file
a conforming PDF/VT-1 or PDF/VT-2 file
3.1.19
PDF/VT file collection
one or more conforming PDF/VT-1 files or PDF/VT-2 file sets, or both
NOTE PDF/VT file collections can include files belonging to several PDF/VT instances.
3.1.20
PDF/VT instance
PDF/VT-1 file, PDF/VT-2 file set or PDF/VT-2s stream
3.1.21
PDF/VT-2 file set
single conforming PDF/VT-2 file and all its referenced PDF files and external ICC profile files
3.1.22
PDF/X-4
conformance level defined in ISO 15930-7
3.1.23
PDF/X-4p
conformance level defined in ISO 15930-7
3.1.24
PDF/X-5
set of conformance levels defined in ISO 15930-8
3.1.25
PDF/X-5g
conformance level defined in ISO 15930-8
3.1.26
PDF/X-5pg
conformance level defined in ISO 15930-8
3.1.27
print element
element intended for final print reproduction
NOTE For more information, see ISO 15930-7.
3.1.28
print product
outcome of the processing of a document through a print manufacturing process.
EXAMPLE A perfect bound book or a postcard.
3.1.29
product part
part of a print product
EXAMPLE The cover part of a saddle-stitched booklet.
3.1.30
reader
software application that is able to read and appropriately process files
[ISO 15930-7]
3.1.31
recipient record
collection of information related to the pages intended for a single recipient
3.1.32
writer
software application that is able to write files
[ISO 15930-7]
4 © ISO 2010 – All rights reserved

3.2 Abbreviated terms
CIP4 International Cooperation for the Integration of Processes in Prepress, Press, and Postpress
Organization
DPM document part metadata
ICC International Color Consortium
JDF Job Definition Format as defined in the CIP4 JDF Specification
PDF Portable Document Format
4 Notations
PDF operators, PDF keywords, the names of keys in PDF dictionaries, and other predefined names are
written in a bold sans serif font; for example, the key Trapped.
Operands of PDF operators or values of dictionary keys are written in an italic sans serif font; for example, the
False value for the Trapped key.
The term “PDF/VT file” indicates requirements for files that comply with at least one of the conformance levels
defined in this part of ISO 16612.
References to the “PDF Reference” are to the Adobe PDF Reference, fifth edition, Version 1.6, as modified by
Errata for the PDF Reference, fifth edition, and by PDF Blend Modes: Addendum.
References to XML are to the Extensible Markup Language defined in Extensible Markup Language
(XML) 1.0 (Second Edition).
5 Conforming files and equipment
5.1 General
This part of ISO 16612 specifies the use of the PDF file format for the exchange of digital data representing
the compound entities of one or more components intended for printing.
This part of ISO 16612, is based on ISO 15930, and defines three conformance levels based on ISO PDF/X
standards as follows.
⎯ PDF/VT-1 requires all compound entities, metadata and resources used in representing graphical content
to be defined within the PDF/VT-1 file as specified in PDF/X-4.
⎯ PDF/VT-2 allows one or more compound entities representing graphical content or ICC profiles required
to render the file to be externally referenced according to the provisions specified in PDF/X-4p, PDF/X-5g
and PDF/X-5pg.
⎯ PDF/VT-2s allows for processing (streaming) of multiple compound entities representing graphical
content before the entire PDF/VT instance has been generated.
PDF/VT conformance is identified in a PDF/VT file by use of the pdfvtid:GTS_PDFVTVersion property as
specified in 6.3. Neither the version number in the header of a PDF file nor the value of the Version key in the
Catalog of a PDF file shall be used in determining whether a file is in accordance with this part of ISO 16612.
A PDF/VT file shall conform to all requirements set out in Clause 6.
5.2 PDF/VT-1 conformance
A PDF/VT-1 conforming writer is a software application that is able to write PDF/VT-1 files in accordance with
the conformance requirements specified in Clause 6.
A PDF/VT-1 conforming reader is a software application or system that is able to read and appropriately
process all PDF/VT-1 files in accordance with the conformance requirements specified in Clause 6.
5.3 PDF/VT-2 conformance
A PDF/VT-2 conforming writer is a software application that is able to write PDF/VT-2 files in accordance with
the conformance requirements specified in Clause 6.
A PDF/VT-2 conforming reader is a software application or system that is able to read and appropriately
process all PDF/VT-2 file sets in accordance with the conformance requirements for PDF/X-4, PDF/X-4p,
PDF/X-5g and PDF/X-5pg as specified in Clause 6.
5.4 PDF/VT-2s conformance
A PDF/VT-2s conforming stream is a MIME package of type application/pdf-vt-stream containing one or more
PDF/VT chunks in which those features necessary for streaming exchange shall adhere to the conformance
requirements defined in Annex A.
A PDF/VT-2s conforming writer is a software application that is able to write PDF/VT-2s streams that are in
accordance with the conformance requirements defined in A.2.
A PDF/VT-2s conforming reader is a software application or system that is able to read and appropriately
process PDF/VT-2s streams in accordance with the conformance requirements defined in A.3.
5.5 All PDF/VT file conformance levels
All conforming interactive readers should present a user interface based on the tree structure of the document
part hierarchy defined in 6.5.
All conforming readers shall read and appropriately process the DPartRoot dictionary and its DPart
sub-dictionaries defined in 6.5.
A conforming editor shall be both a conforming reader and a conforming writer.
All conforming PDF/VT editors, when updating a PDF/VT file, shall write a new value for both the
pdfvtid:GTS_PDFVTModDate and the xmp:ModifyDate properties.
To the extent that ISO 15930-7 and ISO 15930-8 and this part of ISO 16612 permit more than one rendering
of a PDF/VT file, a conforming reader may use a job ticket or metadata information to further restrict the
rendering of the file.
Annex B gives a summary of the permitted PDF/X conformance levels.
5.6 Validation of PDF/VT files
A PDF/VT-1 file can be validated individually against the requirements of this part of ISO 16612.
A PDF/VT-2 file can be validated in isolation against the requirements of this part of ISO 16612. In addition, a
PDF/VT-2 file set can be validated. Successful validation of a PDF/VT-2 file in isolation should not be taken to
imply that the use of that file within a file set would necessarily lead to a conforming file set.
Only a complete PDF/VT-2 file set can be completely validated against the requirements of this part of
ISO 16612. Only a complete PDF/VT-2s stream including all of its referenced files can be completely validated
against the requirements of this part of ISO 16612.
Annex B gives a summary of the permitted PDF/X conformance levels.
6 © ISO 2010 – All rights reserved

6 Technical requirements
6.1 General
The PDF features that shall be required, prohibited or restricted are specified in 6.2 to 6.7. These features
shall be used as prescribed in the PDF Reference and as further restricted by this part of ISO 16612.
6.2 PDF/VT file requirements
6.2.1 PDF/VT-1 file requirements
A PDF/VT-1 file shall conform to PDF/X-4 (but not PDF/X-4p) as defined in ISO 15930-7.
NOTE PDF/X-4p is not included because it permits a reference to an external ICC profile and the PDF/VT-1
conformance level is intended for single-file exchange only.
6.2.2 PDF/VT-2 file requirements
A PDF/VT-2 file shall conform to one of the following:
⎯ PDF/X-5g as defined in ISO 15930-8;
⎯ PDF/X-5pg as defined in ISO 15930-8;
⎯ PDF/X-4p as defined in ISO 15930-7.
NOTE 1 Although PDF/X-5n is a PDF/X-5 conformance level, it is not included in PDF/VT-2 conformance due to the
somewhat specialized nature of digital print workflows that make use of n-colorant data for exchange in variable document
printing applications.
A PDF/VT-2 file shall not reference pages of a PDF/X-5g, PDF/X-5n or PDF/X-5pg conforming file or another
PDF/VT-2 conforming file.
NOTE 2 This requirement means that only pages of PDF/X-1a, PDF/X-3, PDF/X-4, PDF/X-4p, PDF/VT-1 files and
conforming ICC profile files can be referenced.
NOTE 3 The implication of only allowing a conforming PDF/VT-2 file to have an external reference to the noted file
types is that the only secondary reference allowed from a referenced PDF file is to an ICC profile file.
If a referenced page is in a PDF/VT-1 conforming file, the file shall be interpreted as a PDF/X-4 file and its
document part hierarchy and the GTS_Scope key within the referenced file shall be ignored by a conforming
reader.
A conforming PDF/VT-2 file set shall be a conforming PDF/X-5 file set or PDF/X-4p file set.
6.3 PDF/VT-1 and PDF/VT-2 file identification
A PDF/VT-1 or PDF/VT-2 file shall be identified using the pdfvtid:GTS_PDFVTVersion property defined in
Table 1. This property shall be present in the metadata stream associated with the Metadata key in the
document's Catalog as required in ISO 15930-7.
The prefix pdfvtid with the namespace identifier http://www.npes.org/pdfvt/ns/id/ shall always be used as
shown in Table 1.
Table 1 — PDF/VT identification property
Property Value type Category Description
pdfvtid:GTS_PDFVTVersion Text Internal PDF/VT conformance level identifier
pdfvtid:GTS_PDFVTModDate
Date Internal The date and time at which the PDF/VT file
was last written
The values of the pdfvtid:GTS_PDFVTVersion property for PDF/VT files prepared in accordance with this
part of ISO 16612 shall be as shown in Table 2.
Table 2 — Required pdfvtid:GTS_PDFVTVersion values
Conformance level pdfvtid:GTS_PDFVTVersion
PDF/VT-1 PDF/VT-1
PDF/VT-2 PDF/VT-2
NOTE 1 The above conformance levels are for files. The conformance level for a PDF/VT-2s stream is indicated in the
MIME header (see Annex A).
All conforming PDF/VT files shall contain both the pdfvtid:GTS_PDFVTModDate and the xmp:ModifyDate
properties in their XMP metadata and they shall both have the same value.
NOTE 2 The above requirements assist a conforming reader in recognizing whether or not a PDF/VT file has been
modified by a non-conforming PDF/VT editor, because ISO 15930-7 (PDF/X-4) and ISO 15930-8 (PDF/X-5) require the
xmp:ModifyDate to match the value of the ModDate key in the document information dictionary.
NOTE 3 Provisions for PDF/X-4 and PDF/X-5 with regard to the pdfxid:GTS_PDFXVersion entry still apply,
independent of, and in addition to, the provisions in this clause with regard to the GTS_PDFVTVersion entry.
6.4 Architecture
In variable data and transactional document printing, Page Definition Language (PDL) data used to define the
pages of a print job is often an unstructured sequence of page definitions similar to the stream of pages
defined in a PostScript file. Such a print stream defines a specific ordering of recipient pages, each containing
a sequence of one or more pages where the pages are typically imaged by a digital printer in the exact order
they are defined in the PDL file. Such stream-oriented PDL files usually require sequential processing and
contain inline device controls used for such things as print substrate selection, single- or double-sided printing,
and commands for controlling inline converting and finishing devices. These print data streams are usually
device specific and optimized to a particular workflow or to specific capabilities of a target printing device
setup and require specialized applications to generate them. Such PDL data streams are typically not portable
across different production workflows and digital printing devices once they are created.
As a PDF-based structured page description format, PDF/VT encodes the pages of documents in a manner
that allows a conforming reader efficient random access to pages. The random access efficiency of PDF/VT
provides an ideal page content resource format for job-ticket-based workflows where the order of page
processing by a conforming reader can be different from the order presented in the PDF/VT data.
The use of a separate job ticket file for specifying page ordering and reader processing requirements allows
an exchanged PDF/VT instance to be late-stage-targeted or re-targeted to a production workflow, digital
printing device or other messaging channel. Re-targeting or reprinting is possible without the need to recreate
or modify the PDF/VT instance.
The document part hierarchy is a data structure that specifies the sequence and relationship of documents
and/or document parts present in the PDF-VT file. The pages for each recipient are related by one or more
DPart nodes where each node may specify a page range or contain other DPart nodes. The set of pages for
8 © ISO 2010 – All rights reserved

each recipient are defined in a PDF/VT file using a hierarchy of DPart dictionaries referred to as document
part dictionaries. The root node of this hierarchy of dictionaries is identified by the DPartRoot dictionary
referenced from the Catalog dictionary.
The various DPart dictionary nodes of the hierarchy are fully connected by explicit references to the
immediate descendant DPart nodes and to the parent node (refer to Annex C for an example of a DPart
structure).
NOTE 1 Although PDF/VT is based on the PDF Reference, which defines structured access to Page objects via the
pages tree, a conforming reader can also access Page object entries indirectly from the DPart leaf nodes of the document
part hierarchy for a structured presentation of pages.
External job ticket formats such as JDF have specific constructs designed for use with structured PDL formats
that contain metadata in their document part structure. In support of that, PDF/VT provides Document Part
Metadata (DPM) that can occur as a DPM dictionary entry in any DPart dictionary of the document part
hierarchy. DPM is a way by which conforming writers, such as PDF/VT authoring applications, communicate
information about a recipient's documents and document parts to a downstream production workflow or
fulfilment service, or both.
There are many potential uses of DPM. For example, it can be used in a workflow to apply production rules, to
conserve information about intended recipients, or for archival purposes, dynamic bar code printing or slug
line generation.
Conceptually, a PDF/VT file with DPM in combination with the document part hierarchy is analogous to a
structured database of final form variable content pages. This structuring and use of DPM allows a job ticket to
refer to the PDF/VT pages in a way that is conceptually similar to a structured database select or query.
NOTE 2 The JDF 1.4 specification defines constructs that permit a JDF job ticket to specify dynamic production rules
based on the PDF/VT document part hierarchy structure and DPM present within it.
6.5 Document part hierarchy
The Catalog dictionary of a conforming PDF/VT file shall have a DPartRoot key whose value is an indirect
object reference to a DPartRoot dictionary.
In Table 3 and Table 4, the identifiers Required, Optional and Conditional are used to indicate the usage of
the key.
At least one DPart dictionary shall be present in the document part hierarchy.
A Page object shall only be referenced in the range of pages specified by the Start and End keys of a single
DPart dictionary entry.
Each Page object defined in the PDF/VT file shall be included in the page range defined by one and only one
DPart dictionary.
Each Page object shall have a DPart key that has a value that is an indirect reference to the leaf node DPart
dictionary whose range of pages includes this Page object.
NOTE 1 The DPart key in a Page object allows a conforming reader to directly retrieve the section of the document
part hierarchy that applies to this Page object. For example, this allows for efficient retrieval of DPM based on page
indices for certain implementation approaches for cut-and-stack imposition. It also enables ready access of DPM data in
conforming interactive reader applications.

Table 3 — DPartRoot dictionary
a
Key Type Usage of key Value
Type name Optional If present, it shall have the value DPartRoot to identify the
dictionary as a DPartRoot dictionary.
DPartRootNode dictionary Required It shall be present and shall be an indirect reference to the DPart
dictionary that is the root node of the document part hierarchy.
RecordLevel integer Optional If present, this attribute shall identify the zero-based level of the
document part hierarchy where each DPart node of that level
corresponds to a recipient record.
The value 0 corresponds to the DPart node identified by the
value of the DPartRoot dictionary's DPartRootNode key.
NOTE 1 If this key is not present, then recipient records are not
explicitly identified in this file.
NOTE 2 The example in Annex C shows DPart nodes identified by
RecordLevel with child DPart subnodes.
NodeNameList array of names Required It shall be present. Each name entry in this array shall
correspond to a DPart node level of the document part hierarchy
beginning with the DPart dictionary identified by the value of the
DPartRoot dictionary's DPartRootNode key.
The number of entries present in this array shall be equal to the
number of DPart node levels in the document part hierarchy.
Each entry in the NodeNameList array shall conform to the
rules for an XML NMTOKEN after expansion of # escapes.
NOTE The NodeNameList array is used in the interpretation of the
document part hierarchy as XML, as specified in Annex D.
a
The usage of the key is defined as follows:
Required indicates that the key shall be present at all times.
Optional indicates that the key may be present at the discretion of the conforming writer.

The order of Page objects as defined by the page tree shall be the same order in which Page objects are
referenced from leaf node DPart dictionaries in a depth-first traversal of the document part hierarchy.
NOTE 2 By ordering the PDF pages as referenced from the page tree to be in the same order as they are referenced
from DPart leaf nodes of the document part hierarchy, it is possible for existing PDF viewers that do not conform to
PDF/VT and ignore the document part hierarchy to present the pages in the same order as those that follow the document
part hierarchy.
A child DPart dictionary shall not be referenced by more than one parent DPart dictionary.
NOTE 3 The above requirement makes the DPart dictionaries part of a tree structure.
All DPart dictionaries should be written into a conforming PDF/VT file in a single compressed object stream as
defined in PDF Reference, 3.4.6.
NOTE 4 This enables improvement in conforming reader performance (e.g. single read operation) and file size
optimization through the use of compression of similar items. However, performance of random access to the DPart nodes
can be impacted in cases where PDF/VT files have a large number of records. In such a case, multiple compressed object
streams might be preferred.
10 © ISO 2010 – All rights reserved

Table 4 — DPart dictionary
a
Key Type Usage of key Value
Type name Optional If present, it shall have the value DPart to identify the dictionary as
a DPart dictionary.
Parent dictionary Required It shall be present.
If this DPart dictionary is referenced from the DPartRootNode key
of the DPartRoot dictionary, then the value of the Parent key shall
be an indirect reference to the DPartRoot dictionary. In all other
cases, the value of the Parent key shall be an indirect reference to
the DPart dictionary that is its immediate ancestor.
b
array of arrays Conditional It specifies immediate descendent DPart dictionaries and shall be
DParts
present if this DPart dictionary has no Start key and shall not be
present otherwise. If present, the value of this key shall be an
array. Each element in the array shall be an array of indirect
references to immediate descendant DPart dictionaries.
If present, at least one immediate descendent DPart dictionary
shall be specified.
All but the last array entry shall have exactly 8192 elements and
the last array entry shall have at least 1 and at most 8192 entries.
NOTE This definition is intended to allow easy access of many
elements in an efficient way while not limiting the total number of
immediate DPart descendants that can be specified by a DPart dictionary.
b
It shall be present if this DPart dictionary has no DParts key and
Start dictionary Conditional
shall not be present otherwise.
If present, the Start key shall be an indirect reference to the Page
object that defines the first PDF page of the range of pages
belonging to this DPart dictionary.
b
dictionary Conditional It shall be present if this DPart dictionary has a Start key and the
End
page range has more than one page. Otherwise it shall not be
present.
If present, the End key shall be an indirect reference to the Page
object that defines the last PDF page of the range of pages
belonging to this DPart dictionary.
DPM
dictionary Optional If present, it shall specify a dictionary of metadata represented as
key/value pairs.
NOTE See 6.6 for a description of the use of DPM dictionaries for
specifying DPM.
a
The usage of the key is defined as follows:
Required indicates that the key shall be present at all times.
Optional indicates that the key may be present at the discretion of the conforming writer.
Conditional indicates that the presence of the key is dependent on a condition such as the presence or absence of other keys.
b
Only leaf DPart nodes use the Start and End keys and intermediate DPart nodes use the DParts key and no Start and End keys.
Non-leaf DPart dictionary nodes of the hierarchy cannot refer to a range of PDF pages, only to descendent DPart dictionaries.

6.6 Document part metadata (DPM)
DPM is application-specific information communicated between the creator of PDF/VT data and a receiving
system, and can be used to classify the PDF/VT file and its document parts. The receiving system could, for
example, use this information in the purposing of page content to print or to some other messaging channel
for presentation to a recipient. The DPM can also be referenced in a job definition, such as a JDF job ticket, to
vary processing control as necessary during print production.
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