ISO 12639:2004

INTERNATIONAL ISO
STANDARD 12639
Second edition
2004-05-15

Graphic technology — Prepress digital
data exchange — Tag image file format
for image technology (TIFF/IT)
Technologie graphique — Échange de données numériques de
préimpression — Format de fichier d'image d'étiquette pour la
technologie d'image




Reference number
ISO 12639:2004(E)
©
ISO 2004

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ISO 12639:2004(E)
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ISO 12639:2004(E)
Contents Page
Foreword. v
Introduction . vi
1 Scope. 1
2 Compliance levels and identification. 1
2.1 General. 1
2.2 Image file type identification. 1
2.3 TIFF/IT conformance. 2
2.4 TIFF/IT-P1 conformance. 2
2.5 TIFF/IT-P2 conformance. 2
2.6 Conformance identification. 2
3 Normative references. 2
4 Terms, definitions and abbreviated terms. 3
4.1 Terms and definitions. 3
4.2 Abbreviated terms. 5
5 Notations and field types . 5
5.1 Notations. 5
5.2 Field types. 6
6 Image data type description. 7
6.1 Colour continuous-tone picture image (CT) data .7
6.2 Colour line-art (LW) image data. 7
6.3 High-resolution continuous-tone (HC) image data. 7
6.4 Monochrome and binary images. 7
6.5 Final page (FP) data . 8
7 Requirements for TIFF/IT, TIFF/IT-P1 and TIFF/IT-P2 image data files. 8
7.1 Structure of TIFF/IT file. 8
7.2 General parameters. 10
7.3 Colour continuous-tone picture (CT) file. 22
7.4 Colour line-art (LW) file . 25
7.5 High-resolution continuous-tone (HC) file . 32
7.6 Monochrome continuous-tone picture (MP) file . 35
7.7 Binary picture (BP) file . 38
7.8 Binary line-art (BL) file. 40
7.9 Screened data image (SD) file. 42
7.10 Final page (FP) file . 44
Annex A (informative) Background of conformity levels . 50
Annex B (informative) Identification and determination procedures for TIFF/IT file type . 52
Annex C (informative) Relationship between image types on a colour page . 54
Annex D (informative) Alphabetical list of TIFF/IT field names. 55
Annex E (normative) Incorporating JPEG compressed data into TIFF/IT . 57
Annex F (normative) Incorporating Flate compressed data into TIFF/IT. 59
Annex G (normative) RGB colour-space data in TIFF/IT-CT. 61
Annex H (normative) LAB colour space data in TIFF/IT CT . 65
Annex I (informative) Colour values . 68
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ISO 12639:2004(E)
Annex J (normative) ICC Profile tag in TIFF/IT image.69
Annex K (informative) Monochrome continuous-tone picture colour-value calculation .70
Bibliography.74

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ISO 12639:2004(E)
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 12639 was prepared by Technical Committee ISO/TC 130, Graphic technology.
This second edition cancels and replaces the first edition (ISO 12639:1998), which has been technically
revised to add new capabilities, as well as a new constrained conformity level call Profile 2 (P2) to supplement
the previously defined Profile 1 (P1), which is unchanged.
New capabilities include the following:
 expanded LW palette to support up to 65 535 colours;
 support for up to 32 separations;
 new file format “SD” for copydot data with CCITT G4 compression;
 new compression schemes: Flate and JPEG;
 “FP” file format is now defined as normative.

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ISO 12639:2004(E)
Introduction
The goal of ISO/TC 130 in developing the initial version of ISO 12639 was to enable the interchange of
various types of rasterized colour and monochrome image data among electronic digital systems used in
prepress image processing, graphic arts design and related document creation and production operations. It
was, and is, intended for use as a media-independent means for such interchange, and therefore is applicable
to facilitate interchange through a variety of mechanisms such as, but not limited to, network, magnetic and
optical media. Both ISO 12639:1998 and this second edition are based on the Adobe TIFF, Version 6.0 file
format, and both extend and restrict the technical features of that format.
This second edition of ISO 12639, though based on ISO 12639:1998, specifies new capabilities, as well as a
new constrained conformity level called Profile 2 (P2) to supplement the previously defined Profile 1 (P1),
which is unchanged. The key added capabilities include a normative final page (FP) format; a new SD file
format with optional G4 compression for copydot data; definitive ways to use RGB and CIELAB colour spaces
in CT, as well as 16-bit-per-channel data in CT; JPEG compression in CT and MP; Flate compression in all
formats except LW, HC and BL; spot colours (colours other than cyan, magenta, yellow and black) in LW, CT,
HC, MP, BP, BL, and SD; and support for up to 65 535 colours in LW colour palettes. The new P2 compliance
level incorporates all features of P1 and defines a constrained compliance level for these new capabilities.
All of the features of ISO 12639:1998, including the constrained level of conformity called Profile 1 (P1), have
been retained. It should be noted that the P1 formats for CT (Colour Picture), MP (Monochrome Picture), and
BP (Binary Picture) files are compatible with the popular TIFF 6.0 files for CMYK (Separated) Images,
Monochrome Images and Bilevel Images respectively. The P1 formats for HC (High-Resolution Continuous-
Tone), LW (Line-Art) and BL (Binary Line-Art), though not compatible with TIFF 6.0, are designed to be easier
to implement within desktop systems by limiting the range of options and selections. The Profile 1 and 2
formats allow for a broader usage of this International Standard by allowing conformance to simplified,
restricted subsets of functionality supported by many popular application software systems used in the
prepress, graphic arts document processing and computer graphics and imaging industries. A P2-compliant
reader will also read all P1-compliant files.
As a historical note, ISO 12639:1998 was based on the American National Standard ANSI IT8.8, Graphic
technology — Prepress digital data exchange — Tag image file format for image technology (TIFF/IT).

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INTERNATIONAL STANDARD ISO 12639:2004(E)

Graphic technology — Prepress digital data exchange — Tag
image file format for image technology (TIFF/IT)
1 Scope
This International Standard specifies a media-independent means for prepress electronic data exchange
using a tag image file format. This International Standard defines image file formats for encoding colour
continuous-tone picture images, colour line-art images, high-resolution continuous-tone images, monochrome
continuous-tone picture images, binary picture images, binary line-art images, screened data, and images of
composite final pages.
2 Compliance levels and identification
2.1 General
This International Standard has three levels of conformance: TIFF/IT (also referred to as full TIFF/IT),
TIFF/IT-P1 and TIFF/IT-P2. All conformance levels are intended to support a media-independent means for
the exchange of various images used in the prepress, printing, graphic arts, and information processing fields.
TIFF/IT-P1 conformance provides a minimized set of options to permit simpler implementation and
compatibility, where possible (for CT, BP, and MP files), with commonly available TIFF 6.0 readers and writers.
TIFF/IT-P1 is intended for use where the full set of TIFF/IT options is not required.
TIFF/IT-P2 is also a subset of the TIFF/IT specification. TIFF/IT-P2 incorporates all of the options defined for
TIFF/IT-P1 and, in addition, provides support for spot colours, a larger LW colour palette, the SD file format for
screened data, and additional compression methods.
Only those TIFF/IT fields defined in this International Standard are required to be written, recognized and
interpreted by conforming implementations. TIFF fields that are unclassified or not referred to in this
International Standard are not required to be supported for an implementation to conform to this International
Standard. If an unsupported field is read, processing of that field is at the discretion of the reader. The reader
shall follow the strategy described in TIFF and attempt to process the file while ignoring unsupported fields
(see Annex A).
This International Standard specifies the requirements for conforming TIFF/IT, TIFF/IT-P1 and/or TIFF/IT-P2
files for specific image data types. Files for each specific image data type that conform to the requirements of
this International Standard shall be considered conforming TIFF/IT, TIFF/IT-P1 and/or TIFF/IT-P2 files for the
specific image data type. Readers that accept and process these files shall be considered conforming TIFF/IT,
TIFF/IT-P1 or TIFF/IT-P2 readers for the specific image data types. Writers that generate and output these
files shall be considered conforming TIFF/IT, TIFF/IT-P1 or TIFF/IT-P2 writers for the specific image data
types. Where requirements of this International Standard and TIFF 6.0 are in conflict, this International
Standard shall take precedence.
2.2 Image file type identification
TIFF/IT provides the ability to represent the data structure of a wide range of printing and graphic arts images.
The identification of the individual image file types is as follows (see Annex B):
 TIFF/IT-CT colour continuous-tone picture image data;
 TIFF/IT-LW colour line-art image data;
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ISO 12639:2004(E)
 TIFF/IT-HC high-resolution continuous-tone image data;
 TIFF/IT-MP monochrome continuous-tone picture image data;
 TIFF/IT-BP binary picture image data;
 TIFF/IT-BL binary line-art image data;
 TIFF/IT-SD screened data image data;
 TIFF/IT-FP final page data.
2.3 TIFF/IT conformance
For conformance to this International Standard, all image file types do not have to be implemented. Each
image file type described in Clause 7 may be individually implemented. Files, readers or writers may be
identified as conforming for either all image file types or specifically identified image file types.
Conformance with TIFF/IT requires implementation of the requirements for all image file types as described in
Clause 7. Conformance with a specific image file type or types requires identification of the specific image file
type using the identification defined in 2.2 (e.g. TIFF/IT-CT).
2.4 TIFF/IT-P1 conformance
TIFF/IT-P1 conformance provides the ability to represent the data structure of various images in as simple and
straightforward a way as possible in order to support image-file exchange with prepress, printing, graphic arts,
and information processing systems and applications. TIFF/IT-P1 is a subset of TIFF/IT.
Conformance with TIFF/IT-P1 requires implementation of the requirements for all image file types as
described in Clause 7. Conformance with a specific image file type or types requires identification of the
specific image file type using the identification defined in 2.2 with the designation “/P1” appended (e.g.
TIFF/IT-CT/P1).
2.5 TIFF/IT-P2 conformance
TIFF/IT-P2 conformance provides the ability to represent the data structure of various images in as simple and
straightforward a way as possible in order to support image file exchange with prepress, printing, graphic arts,
and information processing systems and applications. TIFF/IT-P2 is a subset of TIFF/IT and forms an
intermediate conformance level between TIFF/IT and TIFF/IT-P1.
Conformance with TIFF/IT-P2 requires implementation of the requirements for all image file types as
described in Clause 7. Conformance with a specific image-file type or types requires identification of the
specific image file type using the identification defined in 2.2 with the designation “/P2” appended (e.g.
TIFF/IT-CT/P2).
2.6 Conformance identification
Conformance with the provisions of this International Standard shall be identified individually for files, readers,
and writers. The accepted terminology shall be the image-file type followed by the designation “file”, “reader”
or “writer” (e.g. TIFF/IT writer, TIFF/IT-CT/P1 reader, TIFF/IT-LW file).
3 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.
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ISO 12639:2004(E)
ISO 3166 (all parts), Codes for the representation of names of countries and their subdivisions
ISO 12641:1997, Graphic technology — Prepress digital data exchange — Colour targets for input scanner
calibration
ISO 12642:1996, Graphic technology — Prepress digital data exchange — Input data for characterization of
4-colour process printing
ISO 13655:1996, Graphic technology — Spectral measurement and colorimetric computation for graphic arts
images
ISO/IEC 646:1991, Information technology — ISO 7-bit coded character set for information interchange
ISO/IEC 10918-1:1994, Information Technology — Digital compression and coding of continuous-tone still
images: Requirements and guidelines.
IEC 61966-2-1:1999, Multimedia Systems and Equipment — Colour Measurement and Management —
Part 2-1: Colour management — Default RGB Colour Space — sRGB
ICC.1:2001-12, File Format for Color Profiles, International Color Consortium
TIFF, Revision 6.0 Final, Aldus Corporation (now Adobe Systems Incorporated), June 3, 1992
RFC:1950, ZLIB Compressed Data Format Specification version 3.3, RFC, 1950: DEUTSCH, P., and J-
L. GAILLY, Aladdin Enterprises, May 1996
RFC:1951, DEFLATE Compressed Data Format Specification version 1.3, RFC, 1951: DEUTSCH, P., Aladdin
Enterprises, May 1996
4 Terms, definitions and abbreviated terms
4.1 Terms and definitions
For the purposes of this document, the following definitions apply.
4.1.1
big-endian
〈byte-ordering〉 method for arranging the sequence of the bytes within a SHORT or LONG from the most
significant to the least significant byte as the byte address increases
4.1.2
little-endian
〈byte-ordering〉 method for arranging the sequence of the bytes within a SHORT or LONG from the least
significant to the most significant byte as the byte address increases
4.1.3
offset
address within a TIFF/IT file relative to byte zero of the file
4.1.4
offset value
SHORT or LONG value containing the offset of a data element
4.1.5
pixel
picture element, or the smallest single building block of a picture containing colour identification and size
(when used to describe dimensions relating to the picture resolution, as in pixels per unit length)
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ISO 12639:2004(E)
4.1.6
printing dot value
printing tone value
·of a data set〉 number, recorded as data in the computer, corresponding to the percentage area on a printing
forme that is intended to accept ink for transfer to the final sheet
NOTE This corresponds to the tone value of a half-tone film. The light end of the final reproduction scale (highlights)
has values approaching 0 % (or often in computer files, 0) and the dark end of the scale (shadows) has values
approaching 100 % (or often in computer files, 255).
4.1.7
reader
application, system or subsystem that accepts a file as its input and performs a level of processing on that file
that, at the minimum, accepts or rejects the file based on predetermined criteria and, if accepted, passes the
file to the next stage of processing
4.1.8
run length encoding
data encoding method in which a sequence of data items, which may include many adjacent repetitions of the
same value, is represented by a sequence of ordered pairs, each consisting of a value and a repeat count
NOTE Run length encoding can result in data compression.
4.1.9
separations
individual planes of data that correspond to the colours to be used in the rendering process
NOTE For “process” colours these are cyan (C), magenta (M), yellow (Y), and black (K). Additional separations are
often required for spot or speciality colours or for image-wise finishing treatments such as varnish.
4.1.10
spot colour
single colorant, identified by name, whose printing tone values are specified independently from colour values
specified in a colour co-ordinate system
4.1.11
string
serial sequence of characters, bytes, integers, etc.
4.1.12
TIFF/IT field
TIFF field
one-dimensional array of values (though most are a single-entry array) having an associated count
NOTE An array is identified by a Field name, a Tag number, and a Field type.
4.1.13
TIFF/IT tag
unique numeric identifier for each entry in the TIFF/IT file
4.1.14
transparent colour
attribute that signifies that the underlying image (if any) shows through
NOTE A clear run is where no colour is present and the underlying image (if any) shows through. The colour “white”
signifies that no underlying image will show through, only the underlying substrate (paper). The “transparent” attribute can
be applied to any or all separations of a pixel run or a palette colour in a LW, HC, BL or BP file.
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ISO 12639:2004(E)
4.1.15
trapping
technique of modifying colour separations to account for dimensional variations in the printing process by
overprinting in selected colours at the boundaries between colours which otherwise might inadvertently be left
uncoloured by normal errors in printing press registration
4.1.16
word-aligned
sequence of bytes beginning at an even offset
4.1.17
writer
application, system or subsystem that generates a file based on predetermined criteria and prepares the file
for output
4.2 Abbreviated terms
BL Binary Line-art (or run length encoded bitmap) image or file
BP Binary Picture (or byte-packed bitmap) image or file
CEPS Colour Electronic Prepress System
CT colour Continuous-Tone picture image or file
DTP Desktop Publishing
FP Final Page file
HC High-resolution Continuous-tone (colour) image or file
IFD Image File Directory
LW colour line-art (or Line-Work) image or file
MP Monochrome continuous-tone Picture image or file
P1 Profile 1
P2 Profile 2
TIFF TIFF, Revision 6.0 Final: Aldus Corporation
SD Screened Data image or file
5 Notations and field types
5.1 Notations
All numeric values in this International Standard are expressed in decimal notation, unless otherwise indicated.
A letter “h” is suffixed to indicate a hexadecimal value. Literal strings are denoted by enclosing them in single
quotation marks.
For character strings, only character values 32 through 126 should be used and letters A through Z and a
through z, respectively, should have the same significance.
Preferred values in TIFF/IT fields are preceded by “=” and enclosed in parentheses, for example “(=5)”.
Preferred values are those values that are required to be accepted and recognized by a compliant application
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ISO 12639:2004(E)
or reader. A compliant application or writer may write values other than preferred values but the reader is not
required to accept or recognize the value. It is left to the discretion of the reader.
Required values in TIFF/IT fields are preceded by “=” but not enclosed in parentheses, for example “=5”.
Required values are those values that are required to be written by a compliant application or writer and are
required to be accepted and recognized by a compliant application or reader.
Default values, if specified, are preceded by “Default =” or “d=”, for example “Default = 0,255”. In some tables,
default values are indicated in a “default value” column. The reader shall assume the default value if no value
is written by the writer in the default-specified field. Because the default values shown for all “TIFF” tag
numbers are those specified for TIFF files, they might not be valid for the particular TIFF/IT file type. In all
such cases, a mandatory field value or values is specified.
NOTE When an entry is made in a “default value” column, it might reference a TIFF 6.0 default value that is not a
valid value for the particular TIFF/IT file type. This is usually indicated by entry of a mandatory field value or values in the
tables.
Classification marks used in this International Standard are defined as follows:
 m Mandatory (absolute requirement) field
The writer is required to include mandatory fields. The reader is required to read and process the field.
The reader is allowed to reject those files where mandatory fields are omitted.
 opt Optional field
The writer may include or omit optional fields. The reader is not required to read or process optional fields.
 d Default field
The writer may include or omit default fields. The reader shall assume the default value for the field if the
field is omitted. The reader is required to read and process the field when it contains any required or
preferred values.
These classifications may vary by file type, and are discussed further in Clause 7.
Image File Directory (IFD) entries are identified by a field name of one or more words, written with initial
capital letters, and no internal spaces (e.g. “PageName”).
5.2 Field types
The field types used in this International Standard are as follows:
 ASCII a field type consisting of a byte containing a graphic character code from ISO/IEC 646;
the last character in an ASCII string shall be a “null” (character 0/0);
 BYTE a field type consisting of an 8-bit unsigned binary integer;
 LONG a field type consisting of a 32-bit unsigned binary integer;
 RATIONAL a field type consisting of two LONGs, the first representing the numerator of a fraction
and the second its denominator;
 SHORT a field type consisting of a 16-bit unsigned binary integer;
 UNDEFINED a field type consisting of an array of 8-bit unsigned binary data.
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ISO 12639:2004(E)
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