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TIFF
™
Revision 6.0
Final — June 3, 1992
Adobe Developers Association A copy of this specification can be found in
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TIFF 6.0 Specification Final—June 3, 1992
Copyright
© 1986-1988, 1992 by Adobe Systems Incorporated. Permission to copy without
fee all or part of this material is granted provided that the copies are not made or
distributed for direct commercial advantage and the Adobe copyright notice ap-
pears. If the majority of the document is copied or redistributed, it must be distrib-
uted verbatim, without repagination or reformatting. To copy otherwise requires
specific permission from the Adobe Systems Incorporated.
Licenses and Trademarks
PostScript is a trademark of Adobe Systems Incorporated. All instances of the
name PostScript in the text are references to the PostScript language as defined by
Adobe Systems Incorporated unless otherwise stated. The name PostScript also is
used as a product trademark for Adobe Systems’ implementation of the PostScript
language interpreter.
Any references to a “PostScript printer,” a “PostScript file,” or a “PostScript
driver” refer to printers, files, and driver programs (respectively) which are writ-
ten in or support the PostScript language. The sentences in this specification that
use “PostScript language” as an adjective phrase are so constructed to reinforce
that the name refers to the standard language definition as set forth by Adobe
Systems Incorporated.
PostScript, the PostScript logo, Display PostScript, Adobe, the Adobe logo,
Adobe Illustrator, Aldus, PageMaker, TIFF, OPI, TrapWise, Tran-Script, Carta,
and Sonata are trademarks of Adobe Systems Incorporated or its subsidiaries, and
may be registered in some jurisdictions.
Apple, LaserWriter, and Macintosh are registered trademarks and Finder and
System 7 are trademarks of Apple, Computer, Inc. Microsoft and MS-DOS are
registered trademarks and Windows is a trademark of Microsoft Corporation.
UNIX is a registered trademark of UNIX System Laboratories, Inc., a wholly
owned subsidiary of Novell, Inc. All other trademarks are the property of their
respective owners.
Production Notes
This document was created electronically using Adobe PageMaker® 6.0.
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TIFF 6.0 Specification Final—June 3, 1992
Contents
Introduction ....................................................................................................................4
About this Specification ...................................................................... 4
Revision Notes ..................................................................................... 6
TIFF Administration .............................................................................8
Information and Support ......................................................................... 8
Private Fields and Values ...................................................................... 8
Submitting a Proposal ............................................................................ 9
The TIFF Advisory Committee ............................................................... 9
Other TIFF Extensions ...........................................................................9
Part 1: Baseline TIFF ....................................................................................................11
Section 1: Notation ............................................................................ 12
Section 2: TIFF Structure ..................................................................13
Section 3: Bilevel Images ..................................................................17
Section 4: Grayscale Images ............................................................ 22
Section 5: Palette-color Images ........................................................ 23
Section 6: RGB Full Color Images .................................................... 24
Section 7: Additional Baseline TIFF Requirements ........................ 26
Section 8: Baseline Field Reference Guide ..................................... 28
Section 9: PackBits Compression .................................................... 42
Section 10: Modified Huffman Compression ................................... 43
Part 2: TIFF Extensions ..............................................................................................48
Section 11: CCITT Bilevel Encodings .............................................. 49
Section 12: Document Storage and Retrieval ................................. 55
Section 13: LZW Compression ......................................................... 57
Section 14: Differencing Predictor ................................................... 64
Section 15: Tiled Images ................................................................... 66
Section 16: CMYK Images ................................................................. 69
Section 17: HalftoneHints ..................................................................72
Section 18: Associated Alpha Handling .......................................... 77
Section 19: Data Sample Format ...................................................... 80
Section 20: RGB Image Colorimetry ................................................ 82
Section 21: YCbCr Images ................................................................ 89
Section 22: JPEG Compression ....................................................... 95
Section 23: CIE L*a*b* Images ........................................................ 110
Part 3: Appendices ....................................................................................................116
Appendix A: TIFF Tags Sorted by Number .................................... 117
Appendix B: Operating System Considerations ........................... 119
Index ...............................................................................120
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TIFF 6.0 Specification Final—June 3, 1992
Introduction
About this Specification
This document describes TIFF, a tag-based file format for storing and interchang-
ing raster images.
History
The first version of the TIFF specification was published by Aldus Corporation in
the fall of 1986, after a series of meetings with various scanner manufacturers and
software developers. It did not have a revision number but should have been la-
beled Revision 3.0 since there were two major earlier draft releases.
Revision 4.0 contained mostly minor enhancements and was released in April
1987. Revision 5.0, released in October 1988, added support for palette color
images and LZW compression.
Scope
TIFF describes image data that typically comes from scanners, frame grabbers,
and paint- and photo-retouching programs.
TIFF is not a printer language or page description language. The purpose of TIFF
is to describe and store raster image data.
A primary goal of TIFF is to provide a rich environment within which applica-
tions can exchange image data. This richness is required to take advantage of the
varying capabilities of scanners and other imaging devices.
Though TIFF is a rich format, it can easily be used for simple scanners and appli-
cations as well because the number of required fields is small.
TIFF will be enhanced on a continuing basis as new imaging needs arise. A high
priority has been given to structuring TIFF so that future enhancements can be
added without causing unnecessary hardship to developers.
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TIFF 6.0 Specification Final—June 3, 1992
Features
• TIFF is capable of describing bilevel, grayscale, palette-color, and full-color
image data in several color spaces.
• TIFF includes a number of compression schemes that allow developers to
choose the best space or time tradeoff for their applications.
• TIFF is not tied to specific scanners, printers, or computer display hardware.
• TIFF is portable. It does not favor particular operating systems, file systems,
compilers, or processors.
• TIFF is designed to be extensible—to evolve gracefully as new needs arise.
• TIFF allows the inclusion of an unlimited amount of private or special-purpose
information.
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TIFF 6.0 Specification Final—June 3, 1992
Revision Notes
Minor changes to TIFF 6.0, March 1995
Updated contact information and TIFF administration policies, since Aldus Cor-
poration merged with Adobe Systems Incorporated on September 1, 1994.
The technical content and pagination are unchanged from the original June 3,
1992 release.
TIFF 5.0 to TIFF 6.0
This revision replaces TIFF Revision 5.0.
In the main body of the document, paragraphs that contain new or substantially-
changed information are shown in italics.
New Features in Revision 6.0
Major enhancements to TIFF 6.0 are described in Part 2. They include:
• CMYK image definition
• A revised RGB Colorimetry section.
• YCbCr image definition
• CIE L*a*b* image definition
• Tiled image definition
• JPEG compression
Clarifications
• The LZW compression section more clearly explains when to switch the cod-
ing bit length.
• The interaction between Compression=2 (CCITT Huffman) and
PhotometricInterpretation was clarified.
• The data organization of uncompressed data (Compression=1) when
BitsPerSample is greater than 8 was clarified. See the Compression field de-
scription.
• The discussion of CCITT Group 3 and Group 4 bilevel image encodings was
clarified and expanded, and Group3Options and Group4Options fields were
renamed T4Options and T6Options. See Section 11.
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TIFF 6.0 Specification Final—June 3, 1992
Organizational Changes
• To make the organization more consistent and expandable, appendices were
transformed into numbered sections.
• The document was divided into two parts—Baseline and Extensions—to help
developers make better and more consistent implementation choices. Part 1,
the Baseline section, describes those features that all general-purpose TIFF
readers should support. Part 2, the Extensions section, describes a number of
features that can be used by special or advanced applications.
• An index and table of contents were added.
Changes in Requirements
• To illustrate a Baseline TIFF file earlier in the document, the material from
Appendix G (“TIFF Classes”) in Revision 5 was integrated into the main body
of the specification . As part of this integration, the TIFF Classes terminology
was replaced by the more monolithic Baseline TIFF terminology. The intent
was to further encourage all mainstream TIFF readers to support the Baseline
TIFF requirements for bilevel, grayscale, RGB, and palette-color images.
• Due to licensing issues, LZW compression support was moved out of the “Part
1: Baseline TIFF” and into “Part 2: Extensions.”
• Baseline TIFF requirements for bit depths in palette-color images were weak-
ened a bit.
Changes in Terminology
In previous versions of the specification, the term “tag” reffered both to the identi-
fying number of a TIFF field and to the entire field. In this version, the term “tag”
refers only to the identifying number. The term “field” refers to the entire field,
including the value.
Compatibility
Every attempt has been made to add functionality in such a way as to minimize
compatibility problems with files and software that were based on earlier versions
of the TIFF specification. The goal is that TIFF files should never become obso-
lete and that TIFF software should not have to be revised more frequently than
absolutely necessary. In particular, Baseline TIFF 6.0 files will generally be read-
able even by older applications that assume TIFF 5.0 or an earlier version of the
specification.
However, TIFF 6.0 files that use one of the major new extensions, such as a new
compression scheme or color space, will not be successfully read by older soft-
ware. In such cases, the older applications must gracefully give up and refuse to
import the image, providing the user with a reasonably informative message.
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TIFF 6.0 Specification Final—June 3, 1992
TIFF Administration
Information and Support
The most recent version of the TIFF specification is available in PDF format on
the Adobe WWW and ftp servers See the cover page of the specification for the
required addresses.
Because of the widespread use of TIFF for in many environments, Adobe is un-
able to provide a general consulting service for TIFF implementors. TIFF devel-
opers are encouraged to study sample TIFF files, read TIFF documentation
thoroughly, and work with developers of other products that are important to you.
If your TIFF question specifically concerns compatibility with an Adobe Systems
product, please contact Adobe Developer Support at devsup-person@adobe.com.
Most companies that use TIFF can answer questions about support for TIFF in
their products. Contact the appropriate product manager or developer support
service group.
Private Fields and Values
An organization might wish to store information meaningful to only that organi-
zation in a TIFF file. Tags numbered 32768 or higher, sometimes called private
tags, are reserved for that purpose.
Upon request, the TIFF administrator (send email to devsup-person@adobe.com)
will allocate and register one or more private tags for an organization, to avoid
possible conflicts with other organizations. You do not need to tell the TIFF ad-
ministrator what you plan to use them for, but giving us this information may help
other developers to avoid some duplication of effort. We will likely make the tag
database public at some point.
Private enumerated values can be accommodated in a similar fashion. For ex-
ample, you may wish to experiment with a new compression scheme within TIFF.
Enumeration constants numbered 32768 or higher are reserved for private usage.
Upon request, the administrator will allocate and register one or more enumerated
values for a particular field (Compression, in our example), to avoid possible
conflicts.
Tags and values allocated in the private number range are not prohibited from
being included in a future revision of this specification. Several such instances
exist in the current TIFF specification.
Do not choose your own tag numbers. Doing so could cause serious compatibility
problems in the future. However, if there is little or no chance that your TIFF files
will escape your private environment, please consider using TIFF tags in the
“reusable” 65000-65535 range. You do not need to contact Adobe when using
numbers in this range.
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TIFF 6.0 Specification Final—June 3, 1992
If you need more than 10 tags, we suggest that you reserve a single private tag,
define it as a LONG TIFF data type, and use its value as a pointer (offset) to a
private IFD or other data structure of your choosing. Within that IFD, you can use
whatever tags you want, since no one else will know that it is an IFD unless you
tell them.
Submitting a Proposal
Any person or group that wants to propose a change or addition to the TIFF speci-
fication should prepare a proposal that includes the following information:
• Name of the person or group making the request, and your affiliation.
• The reason for the request.
• A list of changes exactly as you propose that they appear in the specification.
Use inserts, callouts, or other obvious editorial techniques to indicate areas of
change, and number each change.
• Discussion of the potential impact on the installed base.
• A list of contacts outside your company that support your position. Include
their affiliation.
Please send your proposal to devsup-person@adobe.com.
The TIFF Advisory Committee
The TIFF Advisory Committee is a working group of TIFF experts from a number
of hardware and software manufacturers. It was formed in the spring of 1991 to
provide a forum for debating and refining proposals for the 6.0 release of the TIFF
specification.
If you are a TIFF expert and think you have the time and interest to work on this
committee, contact devsup-person@adobe.com for further information. For the
TIFF 6.0 release, the group met every two or three months, usually on the west
coast of the U.S. Accessibility via Internet email is a requirement for membership,
since that has proven to be an invaluable means for getting work done between
meetings.
Other TIFF Extensions
The Aldus TIFF sections on CompuServe and AppleLink (new location is under
construction; check the Adobe WWW home page (http://www.adobe.com) for
future developements) will contain proposed TIFF extensions from other compa-
nies that are not approved by Adobe as part of Baseline TIFF.
These proposals typically represent specialized uses of TIFF that do not fall
within the domain of publishing or general graphics or picture interchange. Gen-
erally, these features will not be widely supported. If you do write files that incor-
porate these extensions, be sure to either not call them TIFF files or mark them in
some way so that they will not be confused with mainstream TIFF files.
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TIFF 6.0 Specification Final—June 3, 1992
If you have such a document, send it to devsup-person@adobe.com. All submis-
sions must be PDF documents or simple text. Be sure to include contact informa-
tion—at least an email address.
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