ISO 12639:1998

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

Grafična tehnologija - Izmenjava digitalnih podatkov v grafični pripravi - Slikovna tehnologija; slikovni format TIFF/IT

General Information

• Status: Withdrawn
• Publication Date: 23-Sep-1998
• Withdrawal Date: 23-Sep-1998
• ICS: 35.240.30 - IT applications in information, documentation and publishing
• ICS: 37.100.99 - Other standards related to graphic technology
• Technical Committee: ISO/TC 130 - Graphic technology
• Drafting Committee: ISO/TC 130/WG 2 - Prepress data exchange
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 17-May-2004
• Completion Date: 13-Dec-2025
• Ref Project: SIST ISO 12639:2002 - Graphic technology -- Prepress digital data exchange -- Tag image file format for image technology (TIFF/IT)

Relations

• Revised: SIST ISO 12639:2004 - Graphic technology -- Prepress digital data exchange -- Tag image file format for image technology (TIFF/IT)
• Effective Date: 12-May-2008
• Revised: ISO 12639:2004 - Graphic technology - Prepress digital data exchange - Tag image file format for image technology (TIFF/IT)
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL IS0
STANDARD 12639
First edition
1998-I O-01
Graphic technology - Prepress digital data
-Tag image file format for
exchange
image technology (TIFF/IT)
Technologie graphique - khange de don&es numkriques de
prkimpression - Format de fichier d ’image d ’etiquette pour la technologie
d ’image
Reference number
IS0 12639: 1998(E)
IS0 12639: 1998(E)
0 IS0
Contents
Page
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
4 Terms, symbols, abbreviations, and field types . . . . . . . . . . . . . . . . . . . . . . . . 2
5 Conformance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
6 Image data type description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
7 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Annexes
A Relationship between image types on a colour page . . . . . . . . . . . . . . . . . . . 27
B Colour values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
C The Tag Image File Format and TIFF/IT . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
D Final page (FP) file format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
E Identification and determination procedures . . . . . . . . . . . . . . . . . . . . . . . . . 34
F Examples of TIFF/IT-CT and TIFF/IT-CT/P1 files . . . . . . . . . . . . . . . . . . . 35
G Monochrome continuous tone picture colour value calculation . . . . . . . . . . 38
H Alphabetical list of TIFF/IT field names . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
I
Background of the Pl (Profile 1) conformity level - TIFF/IT-P1 . . . . . . . . . 43
0 IS0 1998
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-121 1 Geneve 20 l Switzerland
iso@ iso.ch
Internet
Printed in Switzerland
ii
0 IS0
IS0 12639:1998(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards bodies (IS0 member bodies). The work of preparing
International Standards is normally carried out through IS0 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. IS0 collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
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.
International Standard IS0 12639 was prepared by Technical Committee IS01
TC 130, Graphic technology.
Annexes A to I of this International Standard are for information only.
. . .
IS0 12639: 1998(E)
0 IS0
Introduction
This International Standard was prepared by Working Group 2 (Prepress data
exchange) of ISO/TC 130, Graphic technology, and is based on American National
Standard IT8.8- 1993, Graphic technology - Prepress digital data exchange - Tag
image file format for image technology (TIFF/IT).
.
The technical content of this International Standard enables the interchange of
various types of rasterised colour and monochrome image data files among
electronic, digital systems used in prepress image processing, graphic arts design
and related document creation and production operations. This International
Standard is intended for use as a media-independent means for such interchange,
thus is applicable to facilitate interchange through a variety of mechanisms such as,
though not limited to, network, magnetic and optical media.
The image data types supported by this International Standard include those
specified in IS0 10755: 1992, IS0 10756: 1993, IS0 10759: 1993 (Colour Picture
Data, Colour Line Art Data, and Monochrome Image Data) and also specified in
ANSI IT8.8-1993.
This International Standard, though based on ANSI IT8.8-1993, goes further to
specify a second, more constrained, level of conformity called Profile 1 (PI) for
each image data type. The Pl 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 Pl 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. These Profile 1 formats allow for a broader usage of this
International Standard by allowing conformance to a simplified, restricted subset of
functionality supported by many popular application software systems used in the
prepress, graphic arts document processing and computer graphics and imaging
industries.
In support of backward compatibility, the IT8Header field provides the ability to
include, in TIFF/IT, unmodified headers (appended by an ASCII “null” at the end of
the character string) from IS0 10755, IS0 10756 and IS0 10759. This may be
particularly useful if a file is being transported from one IS0 10755, IS0 10756, or
IS0 10759 environment to another via TIFF/IT. TIFF/IT readers are not required to
interpret and use the contents of the ITSHeader field.
iv
IS0 12639: 1998(E)
0 IS0
Graphic technology - Prepress digital data exchange - Tag image file
format for image technology (TIFF/IT)
data exchange - Monochrome image data on magnetic
1 Scope
tape.
This International Standard specifies a media-independent
IS0 1264 1: 1997, Graphic technology - Prepress digital
means for prepress electronic data exchange. This
data exchange - Colour targets-for input scanner
International Standard defines image file formats for
calibration.
encoding colour continuous tone picture images, colour
line art images, high resolution continuous tone images,
IS0 12642: 1996, Graphic technology - Prepress digital
monochrome continuous tone picture images, binary
- Input data for characterisation of 4 -
data exchange
.
picture images, and binary line art images.
colour process printing.
ANSI CGATS. 15: ‘), Graphic technology - Prepress
2 Normative references
digital data exchange - Three-component color data
definitions.
The following normative documents contain provisions
which, through reference in this text, constitute provisions
TIFF, Revision 6.0 Final: Aldus Corporation (now Adobe
of this International Standard. For dated references,
Systems Incorporated), June 3, 1992.
subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements
based on this International Standard are encouraged to
3 Definitions
investigate the possibility of applying the most recent
editions of the normative documents indicated below. For
For the purposes of this International Standard, the
undated references, the latest edition of the normative
following definitions apply.
document referred to applies. Members of IS0 and IEC
maintain registers of currently valid International
3.1 big-endian (byte-ordering): Method for arranging the
Standards.
sequence of the bytes within a SHORT or LONG from the
most significant to the least significant byte, as the byte
ISO/IEC 646: 1991, Information technology - IS0 7-bit
address increases.
coded character set,for information interchange.
3.2 little-endian (byte-ordering): Method for arranging
IS0 3166: 1993, Codes.for the representation of names qf
.
the sequence of the bytes within a SHORT or LONG from
countries.
the least significant to the most significant byte, as the byte
address increases.
IS0 10755: 1992, Graphic technology - Prepress digital
data exchange - Colour picture data on magnetic tape.
3.3 offset: Address within a TIFF/IT file, relative to byte
zero of the file.
IS0 10756: 1994, Graphic technology - Prepress digital
data exchange - Colour line art data on magnetic tape.
3.4 offset value: SHORT or LONG value within a
TIFF/IT file, containing the offset of a data element.
IS0 10759: 1994, Graphic technology - Prepress digital
1) To be published.
IS0 12639: 1998(E)
0 IS0
3.5 pixel: A picture element, the smallest single building 3.14 trapping: Technique for modifying colour
block of a picture containing colour identification and size separations to account for dimensional variations in the
(when used to describe dimensions relating to the picture printing process by overprinting in selected colours at the
resolution, as in pixels per inch).
boundaries between colours which might inadvertently be
left uncoloured by normal errors in printing press
3.6 printing tone value; printing dot value (of a data registration.
set): Number, recorded as data in the computer,
3.15 word-aligned: Sequence of bytes beginning at an
corresponding to the percentage area on a printing forme
that is intended to accept ink for transfer to the final sheet. even offset.
NOTE 1 This corresponds to the tone value of a half-tone film.
3.16 writer: An application, system or subsystem that
The light end of the final reproduction scale (highlights) will have
generates a file based on predetermined criteria and
values approaching 0% (or often in computer files, 0) and the dark
prepares the file for output.
end of the scale (shadows) will have values approaching 100% (or
often in computer files, 255).
4 Notations, symbols, abbreviations and field
3.7 reader: An application, system or subsystem that
types
accepts a file as its input and performs a level of processing
on that file that, at the minimum, accepts or rejects the file
4.1 Notations
based on predetermined criteria and, if accepted, passes the
file to the next stage of processing.
All numeric values in this International Standard are
expressed in decimal notation, unless otherwise indicated.
3.8 run length encoding: Data encoding method in which
A letter “h” is suffixed to indicate a hexadecimal value.
a sequence of data items, which may include many adjacent
Literal strings are denoted in this International Standard by
repetitions of the same value, is represented by a sequence
enclosing them in single quotation marks. In the
of ordered pairs, each consisting of a value and a repeat
descriptions of file parameters, field names from IS0
count.
10755, IS0 10756, and IS0 10759 are enclosed in
brackets.
NOTE 2 Run length encoding may result in data compression.
Preferred values in TIFF/IT fields are preceded by “=” and
3.9 separations: Individual planes of data that correspond
enclosed in parentheses, for example “(=5) “. Preferred
to each of the single colours to be used in the rendering
values are those values which are required to be accepted
process. For “process” colours these are cyan (C), magenta
and recognized by a compliant application or reader. A
(M), yellow (Y), and black (K). Additional separations are
compliant application or writer may write values other
often required for spot or speciality colours or for
than preferred values but the reader is not required to
imagewise finishing treatments such as varnish.
accept or recognize the value. It is left to the discretion of
the reader.
3.10 string: Serial sequence of characters, bytes, integers,
etc.
Required values in TIFF/IT fields are preceded by I ’=” but
not enclosed in parentheses, for example “=5 ”. Required
3.11 TIFF/IT field, TIFF field: A one-dimensional array
values are those values which are required to be written by
of values (though most are a single-entry array) having an
a compliant application or writer and are required to be
associated count.
accepted and recognized by a compliant application or
reader.
NOTE 3 An array is identified by a Field name, a Tag number,
and a Field type.
Default values, if specified, are preceded by “Default =” or
“d= “, for example “Default = 0,255 ”. In some tables,
3.12 TIFF/IT tag: A unique numeric identifier for each
default values are indicated in a “default value” column.
entry in the TIFF/IT file.
The reader shall assume the default value if no value is
written by the writer in the default-specified field.
3.13 transparent colour: Attribute that signifies that the
Because the default values shown for all “TIFF” tag
underlying image (if any) shows through.
numbers are those specified for TIFF files, they may not be
NOTE 4 A clear run is where no colour is present and the valid for the particular TIFF/IT file type. In all such cases,
underlying image (if any) shows through. The colour “white”
a mandatory field value or values is specified.
signifies that no underlying image should show through, only the
underlying substrate (paper). The “transparent” attribute may be
NOTE 5 When an entry is made in a “default value” column it
applied to any or all separations of a pixel run or a palette colour
might reference a TIFF 6.0 default value that may not be a valid
in a LW, HC, BL or BP file.
value for the particular TIFF/IT file type. This is usually
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IS0 12639: 1998(E)
indicated by entry of a mandatory field value or values in the
Pl Profile 1
tables.
TIFF Tag Image File Format , Version 6.0, Aldus
Classification marks used in clause 7 are defined as
Corporation.
follows:
m Mandatory (Absolute Requirement) field
TIFF/IT TIFF for image technology
The writer is required to include mandatory fields.
The reader is required to read and process the field.
NOTE 6 For character strings, it is recommended that only
The reader is allowed to reject those files where character values 32- 126 be used and to assume letters A-Z and a-z
have the same significance respectively.
mandatory fields are omitted.
4.3 Field types
opt, o Optional field
The writer may include or omit optional fields. The
reader is not required to read or process optional The field types used in this International Standard are as
follows:
fields.
ASCII: A field type consisting of a byte containing a
d Default field
The writer may include or omit default fields. The graphic character code from IS0 646. The
reader shall assume the default value for the field if last character in an ASCII string shall be a
the field is omitted. The reader is required to read “null” (character O/O).
and process the field when it contains any required
BYTE: A field type consisting of an 8-bit unsigned
or preferred values.
binary integer.
These classifications may vary by file type, and are
discussed further in clause 7. LONG: . A field type consisting of a 32-bit unsigned
binary integer.
Image File Directory (IFD) entries are identified by a field
RATIONAL: A field type consisting of two LONGS, the
name of one or more words, written with initial capital
first representing the numerator of a fraction
letters, and no internal spaces (e.g. “PageName ”).
and the second its denqminator.
4.2 Symbols and abbreviations
SHORT: A field type consisting of a 16-bit unsigned
binary integer.
The following symbols and abbreviations are used within
this International Standard with the meanings indicated:
BL binary line art (or run length encoded bitmap) 5 Conformance
image or file
This International Standard has two levels of conformance:
BP binary picture (or byte-packed bitmap) image or TIFF/IT (also referred to as full TIFF/IT) conformance and
file TIFF/IT-P1 conformance. Both conformance levels are
intended to support a media-independent means for the
CEPS Colour Electronic Prepress System exchange of various images used in the prepress, printing,
graphic arts, and information processing fields. TIFF/IT-
CT colour continuous tone picture image or file PI conformance provides a minimized set of options to
permit simpler implementation and compatibility, where
DDES Digital Data Exchange Specification possible (for CT, BP, and MP files), with commonly
available TIFF 6.0 readers and writers. TIFF/IT-P1 is
DTP Desktop Publishing intended for use where the full set of TIFF/IT options is not
required.
HC high resolution continuous tone (colour) image
Only TIFF/IT fields defined in this International Standard
or file
need to be written, recognized and interpreted by
IFD image file directory conforming implementations. TIFF fields that are
unclassified or not referred to in this International Standard
LW colour line art (or line work) image or file are not required to be supported for an implementation to
conform to this International Standard. If an unsupported
MP monochrome continuous tone picture image or field is read, processing of that field is at the discretion of
file the reader. The reader shall follow the strategy described
IS0 12639: 1998(E)
0 IS0
in TIFF and attempt to process the file while ignoring clause 7. Conformance with a specific image file type or
unsupported fields. (See annex I.) types requires identification of the specific image file type
using the identification defined in 5.1 with the designation
This International Standard specifies conforming TIFF/IT
YPl” appended (e.g. TIFF/IT-CT/PI).
and/or TIFF/IT-PI files for specific image data types. Files
for each specific image data type that conform to the
5.4 Conformance identification
requirements of this International Standard shall be
considered conforming TIFF/IT and/or TIFF/IT-P1 files for
Conformance with the provisions of this International
the specific image data type. Readers that accept and
Standard shall be identified individually for files, readers,
process these files shall be considered conforming TIFF/IT
and writers. The accepted terminology shall be the image
or TIFF/IT-P1 readers for the specific image data types.
file type followed by the designation “file ”, “reader ”, or
Writers that generate and output these files shall be
“writer” (e.g. TIFF/IT writer, TIFF/IT-CT/PI reader,
considered conforming TIFF/IT or TIFF/IT-P1 writers for
TIFF/IT-LW file).
the specific image data types. Where requirements of this
International Standard and TIFF 6.0 are in conflict, this
International Standard shall take precedence.
6 Image data type description
5.1 Image file type identification
6.1 Colour continuous tone picture image (CT)
data
TIFF/IT provides the ability to represent the data structure
of a wide range of printing and graphic arts images. The
A colour continuous tone picture image (CT) is a
identification of the individual image file types is as
rectangular array of pixels (picture elements). A pixel is
follows (see annex E):
represented by a set of values corresponding to its colour
components.
TIFF/IT-CT colour continuous tone picture image data
TIFF/IT-LW colour line art image data
NOTE 7 Pixels typically consist of four bytes, representing cyan
TIFF/IT-HC high resolution continuous tone image data
(C), magenta (M), yellow (Y), and black (K) process colours.
TIFF/IT-MP monochrome continuous tone picture image
data
6.2 Colour line art (LW) image data
TIFF/IT-BP binary picture image data
TIFF/IT-BL binary line art image data
A colour line art or line work (LW) image is a rectangular
array of pixels. Each pixel is one of a limited number of
5.2 TIFF/IT conformance
colours. The colours are defined in a palette table which
specifies the values of the colour separation components
For conformance to this International Standard, all image
for each entry in the palette. Line work images have areas
file types do not have to be implemented. Each image file
of many pixels of the same palette entry. Run length
type described in clause 7 may be individually
encoding techniques are used. Underlying images may be
implemented. Files, readers or writers may be identified as
made visible by the use of a transparent colour capability.
conforming for either all image file types or specifically
Colour line art images are normally of higher resolution
identified image file types.
than colour continuous tone picture images (CT).
Conformance with TIFF/IT requires implementation of the
6.3 High resolution continuous tone (HC) image
requirements for all image file types as described in clause
data
7. Conformance with a specific image file type or types
requires identification of the specific image file type using
A high resolution continuous tone (HC) image is a
the identification defined in 5.1 (e.g. TIFF/IT-CT).
rectangular array of pixels. A pixel is represented by a set
of values corresponding to its colour components. It is
5.3 TIFF/IT-P1 conformance
typically at the higher resolution of colour line art. It is
also characterized by a transparent colour capability and
TIFF/IT-P1 conformance provides an ability to represent
run length encoded similar to colour line art. It does not use
the data structure of various images in as simple and
a palette table and as such does not have the same limited
straightforward a way as possible in order to support image
colour representation of colour line art. High resolution
file exchange with prepress, printing, graphic arts, and
continuous tone images are typically used to define the
information processing systems and applications. TIFF/IT-
edges between merged colour continuous tone picture
Pl is a subset of TIFF/IT.
images, and between colour line art and colour continuous
tone picture images.
Conformance with TIFF/IT-PI requires implementation of
the requirements for all image file types as described in
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IS0 12639:1998(E)
NOTE 8 Annex A describes the relationship between CT, LW,
7.1 Structure of TIFF/IT file
and HC images. Annex D describes an additional data type called
Final Page (FP) which describes a completed page.
This International Standard incorporates the notation and
structure as defined in TIFF 6.0 Sections 1 and 2. In
6.4 Monochrome and binary images
addition, those TIFF tags identified but not defined in this
International Standard shall be as defined in TIFF 6.0.
In addition to the colour formats specified in 6.1, 6.2, and
Where requirements of this International Standard and
6.3, monochrome continuous tone and binary DDES
TIFF 6.0 are in conflict, this International Standard shall
images are also supported. These images are similar to
take precedence.
their colour counterparts, except that their formats take
advantage of the reduced amount of data associated with
7.1.1 Overview
monochrome (single colour) and binary images.
A TIFF/IT file conveys image data for a single image or a
6.4.1 Monochrome continuous tone picture image (MP)
set of related images. The TIFF/IT structure includes a
data
short header, one or more Image File Directories (IFD),
and the image data associated with the IFDs. Image
A monochrome continuous tone picture image (MP)
parameters are encoded in tagged fields in the IFD. Fields
consists of a rectangular array of pixels. Each pixel is
that are not used to describe an image are omitted from its
represented by a single byte value indicating the varying
IFD. Each field is identified by its tag value rather than its
intensity of the single image colour at that pixel location.
position in the directory entry.
The intended effect is to reproduce the monochrome
continuous tone picture using various levels of the
7.1.2 Header
specified image colour.
A TIFF/IT file begins with an eight-byte image file header.
The monochrome continuous tone picture format is similar
to, though not identical to, a monochrome version of the
Bytes O-l : The pair of bytes at offset 0 of the file contains
colour continuous tone picture format with a single colour
the IS0 646 characters “11” (4949h) or “MM”
per pixel and is therefore not interleaved.
(4D4Dh). “II” signifies that the file is stored in
little-endian byte order. “MM” signifies that
6.4.2 Binary picture image (BP) data
the file is stored in big-endian byte order. A
writer may write either of the two byte orders.
A binary picture image (BP) consists of a rectangular array
A reader shall interpret both byte orders.
of pixels. Each pixel is represented by a single bit value
indicating that the pixel location is to be part of the
NOTE 9 In normal TIFF usage, this parameter applies to all data
background (bit value 0) or part of the image (bit value 1)
within headers , directories, and image data. In this International
for that pixel location. The bits are ordered left to right Standard, certain 16-bit fields in the image data have a fixed “big-
endian” byte order which will be defined with the specific image
within the byte; i.e. the most significant bit first. A
data types in clause 7.3 through 7.8.
background and a foreground colour may each be
specified.
Bytes 2-3: The pair of bytes (SHORT) at offset 2 contains
the constant 42 (2Ah).
6.4.3 Binary line art image (BL) data
Bytes 4-7: The four bytes (LONG) at offset 4 contain the
A binary line art image (BL) consists of a rectangular array
offset of the first IFD of the file. The directory
of pixels. Each pixel is represented by a single value which
is required to begin on a word-aligned
is encoded as a sequence of pairs of background and image
boundary.
colours.
7.1.3 Image subfiles
The binary line art image is further characterized by having
continuous areas of many pixels of image and background
A TIFF/IT file contains one or more subfiles, each
colour. Run length encoding techniques are used.
representing a single image which may be among a set of
related images in the same TIFF/IT file. Each subfile
consists of an Image File Directory (In>) together with one
7 Requirements
or more referenced word-aligned sequences containing
image data.
The format of the TIFF/IT and TIFF/IT-PI image data files
and the specific requirements for each of the individual
image file types follow. See annex F for examples of the
structure of these files.
IS0 12639:1998(E)
0 IS0
The offsets of the word-aligned sequences containing the
7.1.4 PFD (Image File Directory)
image data for each strip are contained in the data values of
Each IFD is located at an arbitrary word-aligned offset the mandatory StripOffsets field (tag 273, LONG or
within the file. The IFDs are forward-chained together. SHORT, count = StripsPerlmage) .
An IFD consists of a two-byte count of the quantity of IFD
entries within it, one or more IFD entries sorted in The StripByteCounts field (tag 279, LONG or SHORT,
ascending order of tag number, and a four-byte offset to the Count = StripsPerlmage) specifies the number of bytes for
each strip.
next IFD in the chain (zero in the case of the last IFD in the
file). Each IFD entry is a 12-byte field, describing a one-
parameter field that defines an attribute of the file. The structure of a TIFF/IT file containing a single image
subfile is shown in figure 1.
7.1.5 IFD entry
7.2 General parameters
Each IFD entry consists of a SHORT (two-byte) tag
number identifying the field, a SHORT (two-byte) data
This subclause describes, in general terms, each of the
type identifying the field type, a LONG (four-byte) count, fields used in TIFF/IT files. For usage specific to an image
and a LONG (four-byte) offset value. The offset value
file type (i.e. CT, LW, HC, MP, BP, and BL) see the
shall be an even number since the value is expected to be
subclause appropriate to that file type. Annex H provides
on a 16-bit word boundary.
an alphabetical listing of TIFF/IT fields.
The field type codes are: 7.2.1 Job identification
1 BYTE
The job and picture name of the image are described by the
2 ASCII
document name (DocumentName) and image description
3 SHORT
(ImageDescription) fields. The page name (PageName)
4 LONG
field may also be used. Annex H contains an alphabetical
5 RATIONAL
list of TIFF/IT fields.
The count determines the number of data elements in the 269 DocumentName ASCII [Job Name]
value. The count of an ASCII string entry shall be the 270 ImageDescription ASCII [Picture Name, Image
number of characters (bytes) in the string, including the Name]
terminating null character.
285 PageName ASCII
NOTE 10 In the case of an ASCII string, the IS0 10755, IS0
The originator of the image may be identified, and a
10756, and IS0 10759 headers do not have a terminating null,
copyright statement may be included using the Artist and
and so these field sizes are one less than a corresponding TIFF/IT
Copyright fields, respectively.
count with the appended null character.
315 Artist ASCII
33432 Copyright ASCII
The data value associated with an IFD entry is stored
directly in the offset value field of the IFD entry, if its type
7.2.2 System identification
and count combine to indicate a length of four bytes or less.
Otherwise, the offset value field of the IFD entry contains
The following fields may be used to describe system data
the offset of a referenced, word-aligned sequence that
relating to the image:
contains the indicated count of data elements.
271 Make ASCII [Vendor Name]
7.1.6 Image data
ASCII
272 Model
305 Software ASCII [Program Name]
Image data is stored in one or more word-aligned
306 DateTime ASCII
sequences. The array of pixels making up the image may
HostComputer ASCII
be divided into strips. Each strip of an image, except
34016 Site ASCII [Site Name]
possibly the last strip, contains the number of rows
ASCII
340 18 IT8Header
specified in the RowsPerStrip field (tag 278, SHORT or
LONG, default FFFFFFFFh). If RowsPerStrip equals or
It is recommended to include the three-character country
exceeds ImageLength, as is the default, then the entire
code from IS0 3 166 as the last three characters, before the
image is contained within a single strip. Each strip is held
terminating “null” character, of the Make field, to identify
in a single word-aligned sequence of data.
the country of registry of the vendor name.
0 IS0
IS0 12639:1998(E)
TIFF/IT
lmaqe File Header
.
Directory Entry
Byte Order
X
Version Taq .
Xt2
Offset of Type
0th IFD
x+4 I I - I I I -
Count
X+8 Offset
1-1 Y m-1
Value
IFD
Entry Count
B
A
A+2 Directory Entry 0
Directory Entry I
A+14
A+26 Directory Entry 2
Directory Entry n
Y -1 Value
Tag 273
A+2+12B Offset of next IFD
Subfile
f
lmaqe Data
.
Z
Figure 1 - Structure of TIFF/IT file for single image subfile (single strip)
The Site field allows the identity of the location at which 256 ImageWidth SHORT or LONG [pixels
the image was digitized (or encoded into TIFF/IT) to be per line]
included with the file.
257 ImageLength SHORT or LONG [lines in
NOTE 11 The ITSHeader field provides the ability to include
image]
unmodified headers (appended by an ASCII “null” at the end of
274 Orientation SHORT
the character string) from IS0 10755, IS0 10756, and IS0 10759
in the TIFF/IT files. This may be particularly useful if a file is
Basic orientations are specified as follows (see figure 2):
being transported from one IS0 10755, IS0 10756, or IS0 10759
environment to another via TIFF/IT. TIFF/IT readers are not
1=
Load from top left, horizontally (default)
required to interpret and use the contents of the IT8Header field.
the 0th row represents the visual top of the image, and
the 0th column represents the visual left-hand side.
7.2.3 Image size and orientation
5 = Load from top left, vertically
Image size and orientation are defined by three fields. One
the 0th row represents the visual left-hand side of the
field specifies the width of an image, another specifies the
image, and the 0th column represents the visual top.
length of the image, and the third specifies the orientation
of the scan lines with respect to the image content as
4 = Load from bottom left, horizontally
viewed by the end user.
the 0th row represents the visual bottom of the image,

IS0 12639: 1998(E)
0 IS0
Basic
Orientations
5 8
Optional
Orientations
6 3 7
Arrow represents the sequence of the first line of pixels in the data stream
Figure 2 - Relationship between first line of data, image orientation, and orientation code.
(scanlines in image) fields refer to the sequence of pixels in the
and the 0th column represents the visual left-hand side.
data stream and not the logical image itself. The TIFF and
TIFF/IT term “Width” ( “length of line“ in IS0 10755, IS0 10756,
8 = Load from bottom left, vertically
or IS0 10759) refers to the dimension of the image represented by
the 0th row represents the visual left-hand side of the
the first line of pixels in the data stream. The TIFF and TIFF/IT
image, and the 0th column represents the visual
term “Length” ( “breadth of area” in IS0 10755, IS0 10756, or
bottom.
IS0 10759) refers td the dimension of the image represented by
the number of lines in the data stream. For example, orientations
Conformance to this International Standard requires that at
” 1” and “4” define “Width” as the horizontal axis of the logical
least one basic orientation be written and all four basic
image, and “Length” as the vertical axis. Orientations “5” and “8”
orientations be read.
define “Width” as the vertical axis and “Length” as the horizontal
axis.
Optional orientations are specified as follows (see figure
.
7.2.4 Image resolution
.
2)
282 XResolution RATIONAL [resolution of line]
2 = Load from top right, horizontally
283 YResolution RATIONAL [resolution of
the 0th row represents the visual top of the image, and
breadth]
the 0th column represents the right-hand side.
296 ResolutionUnit SHORT
6= Load from top right, vertically
The resolution (number of pixels per ResolutionUnit) may
the 0th row represents the visual right-hand side of the
be specified in both the Width (line) and Length (breadth)
image, and the 0th column represents the visual top.
directions. The values for ResolutionUnit for TIFF/IT and
TIFF/IT-PI conformity levels shall be centimetres
3= Load from bottom right, horizontally
represented by value 3 and inches represented by value 2
the 0th row represents the visual bottom of the image,
(default value) in field 296. The other value recognized by
and the 0th column represents the visual right-hand
TIFF, but not by TIFF/IT, is 1, meaning no absolute unit of
side.
measurement is specified.
7= Load from bottom right, vertically
Pixels do not need to be square in size. To properly size an
the 0th row represents the visual right-hand side of the
image, the resolution of both axes must be considered. The
image, and the 0th column represents the visual
necessary information is provided by the resolution
bottom.
specifications for each axis, and the number of pixels for
NOTE 12 IS0 10755, IS0 10756, and IS0 10759 made
each axis. From this, the size of each axis may be
provision for unknown orientations; TIFF/IT does not.
determined by dividing the number of pixels by the
resolution.
NOTE 13 The size, resolution, and orientation fields interact to
describe the size and orientation of the logical image in the data
stream. The ImageWidth (pixels per scanline) and ImageLength
0 IS0
IS0 12639:1998(E)
Table 1
- Encoding of data format
File Type SamplesPerPixel
BitsPerSample Compression PlanarConfiguration
Colour continuous tone picture 1-16 8, 8, . . . 1 or 32895 1
(CT) - pixel interleaved
Colour continuous tone picture 1-16 8, 8, . . . 1 or 32895 32768
(CT) - line interleaved
Colour continuous tone picture 1-16 8, 8, . . . 1 or 32895 2
(CT) - colour interleaved
Colour line art (LW) 1 8 32896 omit, not used
High resolution continuous tone 2 -16 8, 8, . . . 32897 1
even values only
WC)
Monochrome continuous tone 1 8 1 or 32895 omit, not used
picture (MP)
Binary picture (BP) 1 1 1 omit, not used
Binary line art (BL) 1 1 32898 omit, not used
7.2.5 Data format the run length encoding scheme for the BL format
(value 32898)
The data format parameters describe the style and order of
the data stream. A number of TIFF/IT fields are used to PlanarConfiguration distinguishes between CT formats that
are pixel (sometimes referred to as “chunky ”), line or
encode them.
colour (i.e. colour plane or separation) interleaved, by
254 NewSubfileType LONG values 1, 32768, and 2 respectively. The value defaults to
1, and the field may be omitted when SamplesPerPixel
NewSubfileType is a general indication of the kind of data equals 1.
contained in the subfile. The value is made up of 32 flag
bits. Unused bits shall be 0. Bit 0 is the low-order bit. Table 1 summarizes how the data formats for the different
file types are encoded by these TIFF/IT fields.
258 BitsPerSample SHORT
259 Compression SHORT 340 19 RasterPadding SHORT
277 SamplesPerPixel SHORT
284 Planarconfiguration SHORT The RasterPadding field allows each line of colour or
interleaved colours to be padded to a 1-, 2-, 4-, 5 12-, or
The fields SamplesPerPixel and BitsPerSample determine 1024-byte boundary.
the number of samples (separations, colours) and their size.
This information, with that provided in the fields 0 = byte raster (default value) - pad to 1 byte
Compression and PlanarConfiguration, determine the 1 = word raster - pad to 2 bytes
format of the data in the file. The count of BitsPerSample 2 = long word raster - pad to 4 bytes
9 = sector raster - pad to 5 12 bytes
data elements shall equal the value of the SamplesPerPixel
10 = long sector raster - pad to 1024 bytes
fields.
When applied to line interleaved data, this field relates to
If the value of Compression is the default value of “l”,
each line of colour, rather than to each line of pixels. The
there is no compression. (The BP data format packs data
value of the field is the power of two corresponding to the
into bytes as tightly as possible, with no unused bits except
at the end of a row.) The other TIFF/IT values of the padding length (in bytes).
compression indicate:
Two additional fields are required for the TIFF/IT-LW line
the use of RasterPadding in the CT or MP format art files. They describe the number of bits required to
describe short and long runs. See the individual file type
(value 32895)
for more information.
the run length encoding scheme for the LW format
(value 32896)
34020 BitsPerRunLength SHORT (default = 8)
the run length encoding scheme for the HC format
3402 1 BitsPerExtendedRunLength SHORT (default = 16)
(value 32897)
IS0 12639: 1998(E)
0 IS0
The HC file has specific usages which determine the type 7.2.7.2 Colour sequence
of information contained within the file. HCUsage is an
indicator of the type of information contained within the
262 PhotometricInterpretation SHORT (=5 for
HC file.
separations)
340 17 ColorSequence ASCII [Sequence of
34030 HCUsage
LONG Colours ]
The bits of HCUsage indicate the type of information Value 5 for PhotometricInterpretation for CT, LW, and HC
contained in the HC file. If all bits are 0, or the field is not images signifies separated image file data in the sequence
present, the information type is unknown. Each bit
CMYK, or a separated image file data in other colours or
indicates a type of information which may be coded in the
sequences if modified by other fields. Values 0 and 1 are
file, the bits are not mutually exclusive since an HC file used for MP, BP, and BL images.
may contain both contone and line art information:
This International Standard provides for two basic colour
bit 0: 1 means the file contains high resolution CT sequences describing four-colour separations. These basic
contone information colour sequences are specified by values “CMYK” and
bit 1: 1 means the file contains line art (line work) “YMCK” in the ColorSequence field.
information
bit 2: 1 means the file contains trapping information To specify optional colours or colour sequences in this
bit 3-3 1: Reserved, must contain zeroes International Standard, the following entries in the
ColorSequence field may be used in any sequence (colour
7.2.6 File format entries may be repeated for additional separations of the
same colour):
Many prepress applications use only one strip in the
IIYII "M" "Cll "K" =
TIFF/IT formats. In these cases, there will be only one Yellow, magenta, cyan, and black
strip offset and byte count, and the RowsPerStrip field may inks
“R” IIG” IIB 11
be omitted. In other cases, the usage of StripOffsets, = Red, green, blue light intensity
“U” yt “L”
RowsPerStrip, and StripByteCounts fields are as described = CIE 1976 projective u ’, v ’, and
in TIFF 6.0, Part 1: Baseline.
photopic luminance (Y)
” 1 ” to “9” = User-definable colours or
S tripoffsets
273 LONG or SHORT separations; such as pink, varnish,
278 RowsPerStrip LONG or SHORT etc.
11 11
279 S tripByteCounts LONG or SHORT = Present in the data stream but ignored
Q
See 7.1.6 for the use of these parameters. The use of ColorSequence for RGB images is discouraged.
The TIFF 6.0 specification, Section 6: RGB Full Colour
7.2.7 Colour specification Images, should be used unless TIFF/IT specific features
and functionality is required for RGB images.
The primary colour space for this International Standard is
CMYK, with other colour spaces provided for as described NOTE 14 The “Sequence of Colours” field in IS0 10755, IS0
10756, and IS0 10759 is fixed-length and space-padded: the
below. The parameters for specifying the colour space are:
TIFF/IT ColorSequence field is variable-length and null-
terminated.
- the number of colour separations,
- the colour sequence,
NOTE 15 Other colour sequences for red, green, blue are
- the colour values.
unlikely to be found. UVL is also unlikely to be found. They are
retained only for backward compatibility with IS0 10755 and IS0
7.2.7.1 Number of colour separations
10756. A future revision of this International Standard is likely to
include an encoding for the CIELAB and CIEXYZ colour
Images for printing are typically represented by the four
representations.
separations of process colour inks, in either CMYK or
YMCK order. Optionally, one to sixteen separations with
PhotometricInterpretation values of “0” and ” 1” shall be
varied sequences can be described as specified in 7.2.7.2.
used for MP, BP, and BL images. Value of “0” means
SamplesPerPixel specifies the number of separations
“WhiteIsZero” (0 is imaged as white) and value of ” 1”
except for the line art (LW) file type. For LW, the number
means “BlackIsZero” (0 is imaged as black). In TIFF/IT,
of separations is specified as the number of colour entries
the value “0” is recommended for MP, BP, and BL images.
specified in the ColorSequence field.
In TIFF/IT, MP, BP, and BL images, the terms white and
black in WhiteIsZero and BlackIsZero should be replaced
with BackgroundColor and ImageColor (foreground
0 IS0
IS0 12639: 1998(E)
colour) for proper interpretation.
values specified for 0% dot and 100% dot. In this case, it
is at the discretion of the reader to either accept or truncate
332 InkSet SHORT the data.
...

SLOVENSKI STANDARD
01-november-2002
*UDILþQDWHKQRORJLMD,]PHQMDYDGLJLWDOQLKSRGDWNRYYJUDILþQLSULSUDYL6OLNRYQD
WHKQRORJLMDVOLNRYQLIRUPDW7,)),7
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
Ta slovenski standard je istoveten z: ISO 12639:1998
ICS:
35.240.30 Uporabniške rešitve IT v IT applications in information,
informatiki, dokumentiranju in documentation and
založništvu publishing
37.100.99 'UXJLVWDQGDUGLY]YH]L] Other standards related to
JUDILþQRWHKQRORJLMR graphic technology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL IS0
STANDARD 12639
First edition
1998-I O-01
Graphic technology - Prepress digital data
-Tag image file format for
exchange
image technology (TIFF/IT)
Technologie graphique - khange de don&es numkriques de
prkimpression - Format de fichier d ’image d ’etiquette pour la technologie
d ’image
Reference number
IS0 12639: 1998(E)
IS0 12639: 1998(E)
0 IS0
Contents
Page
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
4 Terms, symbols, abbreviations, and field types . . . . . . . . . . . . . . . . . . . . . . . . 2
5 Conformance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
6 Image data type description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
7 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Annexes
A Relationship between image types on a colour page . . . . . . . . . . . . . . . . . . . 27
B Colour values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
C The Tag Image File Format and TIFF/IT . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
D Final page (FP) file format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
E Identification and determination procedures . . . . . . . . . . . . . . . . . . . . . . . . . 34
F Examples of TIFF/IT-CT and TIFF/IT-CT/P1 files . . . . . . . . . . . . . . . . . . . 35
G Monochrome continuous tone picture colour value calculation . . . . . . . . . . 38
H Alphabetical list of TIFF/IT field names . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
I
Background of the Pl (Profile 1) conformity level - TIFF/IT-P1 . . . . . . . . . 43
0 IS0 1998
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-121 1 Geneve 20 l Switzerland
iso@ iso.ch
Internet
Printed in Switzerland
ii
0 IS0
IS0 12639:1998(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards bodies (IS0 member bodies). The work of preparing
International Standards is normally carried out through IS0 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. IS0 collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
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.
International Standard IS0 12639 was prepared by Technical Committee IS01
TC 130, Graphic technology.
Annexes A to I of this International Standard are for information only.
. . .
IS0 12639: 1998(E)
0 IS0
Introduction
This International Standard was prepared by Working Group 2 (Prepress data
exchange) of ISO/TC 130, Graphic technology, and is based on American National
Standard IT8.8- 1993, Graphic technology - Prepress digital data exchange - Tag
image file format for image technology (TIFF/IT).
.
The technical content of this International Standard enables the interchange of
various types of rasterised colour and monochrome image data files among
electronic, digital systems used in prepress image processing, graphic arts design
and related document creation and production operations. This International
Standard is intended for use as a media-independent means for such interchange,
thus is applicable to facilitate interchange through a variety of mechanisms such as,
though not limited to, network, magnetic and optical media.
The image data types supported by this International Standard include those
specified in IS0 10755: 1992, IS0 10756: 1993, IS0 10759: 1993 (Colour Picture
Data, Colour Line Art Data, and Monochrome Image Data) and also specified in
ANSI IT8.8-1993.
This International Standard, though based on ANSI IT8.8-1993, goes further to
specify a second, more constrained, level of conformity called Profile 1 (PI) for
each image data type. The Pl 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 Pl 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. These Profile 1 formats allow for a broader usage of this
International Standard by allowing conformance to a simplified, restricted subset of
functionality supported by many popular application software systems used in the
prepress, graphic arts document processing and computer graphics and imaging
industries.
In support of backward compatibility, the IT8Header field provides the ability to
include, in TIFF/IT, unmodified headers (appended by an ASCII “null” at the end of
the character string) from IS0 10755, IS0 10756 and IS0 10759. This may be
particularly useful if a file is being transported from one IS0 10755, IS0 10756, or
IS0 10759 environment to another via TIFF/IT. TIFF/IT readers are not required to
interpret and use the contents of the ITSHeader field.
iv
IS0 12639: 1998(E)
0 IS0
Graphic technology - Prepress digital data exchange - Tag image file
format for image technology (TIFF/IT)
data exchange - Monochrome image data on magnetic
1 Scope
tape.
This International Standard specifies a media-independent
IS0 1264 1: 1997, Graphic technology - Prepress digital
means for prepress electronic data exchange. This
data exchange - Colour targets-for input scanner
International Standard defines image file formats for
calibration.
encoding colour continuous tone picture images, colour
line art images, high resolution continuous tone images,
IS0 12642: 1996, Graphic technology - Prepress digital
monochrome continuous tone picture images, binary
- Input data for characterisation of 4 -
data exchange
.
picture images, and binary line art images.
colour process printing.
ANSI CGATS. 15: ‘), Graphic technology - Prepress
2 Normative references
digital data exchange - Three-component color data
definitions.
The following normative documents contain provisions
which, through reference in this text, constitute provisions
TIFF, Revision 6.0 Final: Aldus Corporation (now Adobe
of this International Standard. For dated references,
Systems Incorporated), June 3, 1992.
subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements
based on this International Standard are encouraged to
3 Definitions
investigate the possibility of applying the most recent
editions of the normative documents indicated below. For
For the purposes of this International Standard, the
undated references, the latest edition of the normative
following definitions apply.
document referred to applies. Members of IS0 and IEC
maintain registers of currently valid International
3.1 big-endian (byte-ordering): Method for arranging the
Standards.
sequence of the bytes within a SHORT or LONG from the
most significant to the least significant byte, as the byte
ISO/IEC 646: 1991, Information technology - IS0 7-bit
address increases.
coded character set,for information interchange.
3.2 little-endian (byte-ordering): Method for arranging
IS0 3166: 1993, Codes.for the representation of names qf
.
the sequence of the bytes within a SHORT or LONG from
countries.
the least significant to the most significant byte, as the byte
address increases.
IS0 10755: 1992, Graphic technology - Prepress digital
data exchange - Colour picture data on magnetic tape.
3.3 offset: Address within a TIFF/IT file, relative to byte
zero of the file.
IS0 10756: 1994, Graphic technology - Prepress digital
data exchange - Colour line art data on magnetic tape.
3.4 offset value: SHORT or LONG value within a
TIFF/IT file, containing the offset of a data element.
IS0 10759: 1994, Graphic technology - Prepress digital
1) To be published.
IS0 12639: 1998(E)
0 IS0
3.5 pixel: A picture element, the smallest single building 3.14 trapping: Technique for modifying colour
block of a picture containing colour identification and size separations to account for dimensional variations in the
(when used to describe dimensions relating to the picture printing process by overprinting in selected colours at the
resolution, as in pixels per inch).
boundaries between colours which might inadvertently be
left uncoloured by normal errors in printing press
3.6 printing tone value; printing dot value (of a data registration.
set): Number, recorded as data in the computer,
3.15 word-aligned: Sequence of bytes beginning at an
corresponding to the percentage area on a printing forme
that is intended to accept ink for transfer to the final sheet. even offset.
NOTE 1 This corresponds to the tone value of a half-tone film.
3.16 writer: An application, system or subsystem that
The light end of the final reproduction scale (highlights) will have
generates a file based on predetermined criteria and
values approaching 0% (or often in computer files, 0) and the dark
prepares the file for output.
end of the scale (shadows) will have values approaching 100% (or
often in computer files, 255).
4 Notations, symbols, abbreviations and field
3.7 reader: An application, system or subsystem that
types
accepts a file as its input and performs a level of processing
on that file that, at the minimum, accepts or rejects the file
4.1 Notations
based on predetermined criteria and, if accepted, passes the
file to the next stage of processing.
All numeric values in this International Standard are
expressed in decimal notation, unless otherwise indicated.
3.8 run length encoding: Data encoding method in which
A letter “h” is suffixed to indicate a hexadecimal value.
a sequence of data items, which may include many adjacent
Literal strings are denoted in this International Standard by
repetitions of the same value, is represented by a sequence
enclosing them in single quotation marks. In the
of ordered pairs, each consisting of a value and a repeat
descriptions of file parameters, field names from IS0
count.
10755, IS0 10756, and IS0 10759 are enclosed in
brackets.
NOTE 2 Run length encoding may result in data compression.
Preferred values in TIFF/IT fields are preceded by “=” and
3.9 separations: Individual planes of data that correspond
enclosed in parentheses, for example “(=5) “. Preferred
to each of the single colours to be used in the rendering
values are those values which are required to be accepted
process. For “process” colours these are cyan (C), magenta
and recognized by a compliant application or reader. A
(M), yellow (Y), and black (K). Additional separations are
compliant application or writer may write values other
often required for spot or speciality colours or for
than preferred values but the reader is not required to
imagewise finishing treatments such as varnish.
accept or recognize the value. It is left to the discretion of
the reader.
3.10 string: Serial sequence of characters, bytes, integers,
etc.
Required values in TIFF/IT fields are preceded by I ’=” but
not enclosed in parentheses, for example “=5 ”. Required
3.11 TIFF/IT field, TIFF field: A one-dimensional array
values are those values which are required to be written by
of values (though most are a single-entry array) having an
a compliant application or writer and are required to be
associated count.
accepted and recognized by a compliant application or
reader.
NOTE 3 An array is identified by a Field name, a Tag number,
and a Field type.
Default values, if specified, are preceded by “Default =” or
“d= “, for example “Default = 0,255 ”. In some tables,
3.12 TIFF/IT tag: A unique numeric identifier for each
default values are indicated in a “default value” column.
entry in the TIFF/IT file.
The reader shall assume the default value if no value is
written by the writer in the default-specified field.
3.13 transparent colour: Attribute that signifies that the
Because the default values shown for all “TIFF” tag
underlying image (if any) shows through.
numbers are those specified for TIFF files, they may not be
NOTE 4 A clear run is where no colour is present and the valid for the particular TIFF/IT file type. In all such cases,
underlying image (if any) shows through. The colour “white”
a mandatory field value or values is specified.
signifies that no underlying image should show through, only the
underlying substrate (paper). The “transparent” attribute may be
NOTE 5 When an entry is made in a “default value” column it
applied to any or all separations of a pixel run or a palette colour
might reference a TIFF 6.0 default value that may not be a valid
in a LW, HC, BL or BP file.
value for the particular TIFF/IT file type. This is usually
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IS0 12639: 1998(E)
indicated by entry of a mandatory field value or values in the
Pl Profile 1
tables.
TIFF Tag Image File Format , Version 6.0, Aldus
Classification marks used in clause 7 are defined as
Corporation.
follows:
m Mandatory (Absolute Requirement) field
TIFF/IT TIFF for image technology
The writer is required to include mandatory fields.
The reader is required to read and process the field.
NOTE 6 For character strings, it is recommended that only
The reader is allowed to reject those files where character values 32- 126 be used and to assume letters A-Z and a-z
have the same significance respectively.
mandatory fields are omitted.
4.3 Field types
opt, o Optional field
The writer may include or omit optional fields. The
reader is not required to read or process optional The field types used in this International Standard are as
follows:
fields.
ASCII: A field type consisting of a byte containing a
d Default field
The writer may include or omit default fields. The graphic character code from IS0 646. The
reader shall assume the default value for the field if last character in an ASCII string shall be a
the field is omitted. The reader is required to read “null” (character O/O).
and process the field when it contains any required
BYTE: A field type consisting of an 8-bit unsigned
or preferred values.
binary integer.
These classifications may vary by file type, and are
discussed further in clause 7. LONG: . A field type consisting of a 32-bit unsigned
binary integer.
Image File Directory (IFD) entries are identified by a field
RATIONAL: A field type consisting of two LONGS, the
name of one or more words, written with initial capital
first representing the numerator of a fraction
letters, and no internal spaces (e.g. “PageName ”).
and the second its denqminator.
4.2 Symbols and abbreviations
SHORT: A field type consisting of a 16-bit unsigned
binary integer.
The following symbols and abbreviations are used within
this International Standard with the meanings indicated:
BL binary line art (or run length encoded bitmap) 5 Conformance
image or file
This International Standard has two levels of conformance:
BP binary picture (or byte-packed bitmap) image or TIFF/IT (also referred to as full TIFF/IT) conformance and
file TIFF/IT-P1 conformance. Both conformance levels are
intended to support a media-independent means for the
CEPS Colour Electronic Prepress System exchange of various images used in the prepress, printing,
graphic arts, and information processing fields. TIFF/IT-
CT colour continuous tone picture image or file PI conformance provides a minimized set of options to
permit simpler implementation and compatibility, where
DDES Digital Data Exchange Specification possible (for CT, BP, and MP files), with commonly
available TIFF 6.0 readers and writers. TIFF/IT-P1 is
DTP Desktop Publishing intended for use where the full set of TIFF/IT options is not
required.
HC high resolution continuous tone (colour) image
Only TIFF/IT fields defined in this International Standard
or file
need to be written, recognized and interpreted by
IFD image file directory conforming implementations. TIFF fields that are
unclassified or not referred to in this International Standard
LW colour line art (or line work) image or file are not required to be supported for an implementation to
conform to this International Standard. If an unsupported
MP monochrome continuous tone picture image or field is read, processing of that field is at the discretion of
file the reader. The reader shall follow the strategy described
IS0 12639: 1998(E)
0 IS0
in TIFF and attempt to process the file while ignoring clause 7. Conformance with a specific image file type or
unsupported fields. (See annex I.) types requires identification of the specific image file type
using the identification defined in 5.1 with the designation
This International Standard specifies conforming TIFF/IT
YPl” appended (e.g. TIFF/IT-CT/PI).
and/or TIFF/IT-PI files for specific image data types. Files
for each specific image data type that conform to the
5.4 Conformance identification
requirements of this International Standard shall be
considered conforming TIFF/IT and/or TIFF/IT-P1 files for
Conformance with the provisions of this International
the specific image data type. Readers that accept and
Standard shall be identified individually for files, readers,
process these files shall be considered conforming TIFF/IT
and writers. The accepted terminology shall be the image
or TIFF/IT-P1 readers for the specific image data types.
file type followed by the designation “file ”, “reader ”, or
Writers that generate and output these files shall be
“writer” (e.g. TIFF/IT writer, TIFF/IT-CT/PI reader,
considered conforming TIFF/IT or TIFF/IT-P1 writers for
TIFF/IT-LW file).
the specific image data types. Where requirements of this
International Standard and TIFF 6.0 are in conflict, this
International Standard shall take precedence.
6 Image data type description
5.1 Image file type identification
6.1 Colour continuous tone picture image (CT)
data
TIFF/IT provides the ability to represent the data structure
of a wide range of printing and graphic arts images. The
A colour continuous tone picture image (CT) is a
identification of the individual image file types is as
rectangular array of pixels (picture elements). A pixel is
follows (see annex E):
represented by a set of values corresponding to its colour
components.
TIFF/IT-CT colour continuous tone picture image data
TIFF/IT-LW colour line art image data
NOTE 7 Pixels typically consist of four bytes, representing cyan
TIFF/IT-HC high resolution continuous tone image data
(C), magenta (M), yellow (Y), and black (K) process colours.
TIFF/IT-MP monochrome continuous tone picture image
data
6.2 Colour line art (LW) image data
TIFF/IT-BP binary picture image data
TIFF/IT-BL binary line art image data
A colour line art or line work (LW) image is a rectangular
array of pixels. Each pixel is one of a limited number of
5.2 TIFF/IT conformance
colours. The colours are defined in a palette table which
specifies the values of the colour separation components
For conformance to this International Standard, all image
for each entry in the palette. Line work images have areas
file types do not have to be implemented. Each image file
of many pixels of the same palette entry. Run length
type described in clause 7 may be individually
encoding techniques are used. Underlying images may be
implemented. Files, readers or writers may be identified as
made visible by the use of a transparent colour capability.
conforming for either all image file types or specifically
Colour line art images are normally of higher resolution
identified image file types.
than colour continuous tone picture images (CT).
Conformance with TIFF/IT requires implementation of the
6.3 High resolution continuous tone (HC) image
requirements for all image file types as described in clause
data
7. Conformance with a specific image file type or types
requires identification of the specific image file type using
A high resolution continuous tone (HC) image is a
the identification defined in 5.1 (e.g. TIFF/IT-CT).
rectangular array of pixels. A pixel is represented by a set
of values corresponding to its colour components. It is
5.3 TIFF/IT-P1 conformance
typically at the higher resolution of colour line art. It is
also characterized by a transparent colour capability and
TIFF/IT-P1 conformance provides an ability to represent
run length encoded similar to colour line art. It does not use
the data structure of various images in as simple and
a palette table and as such does not have the same limited
straightforward a way as possible in order to support image
colour representation of colour line art. High resolution
file exchange with prepress, printing, graphic arts, and
continuous tone images are typically used to define the
information processing systems and applications. TIFF/IT-
edges between merged colour continuous tone picture
Pl is a subset of TIFF/IT.
images, and between colour line art and colour continuous
tone picture images.
Conformance with TIFF/IT-PI requires implementation of
the requirements for all image file types as described in
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IS0 12639:1998(E)
NOTE 8 Annex A describes the relationship between CT, LW,
7.1 Structure of TIFF/IT file
and HC images. Annex D describes an additional data type called
Final Page (FP) which describes a completed page.
This International Standard incorporates the notation and
structure as defined in TIFF 6.0 Sections 1 and 2. In
6.4 Monochrome and binary images
addition, those TIFF tags identified but not defined in this
International Standard shall be as defined in TIFF 6.0.
In addition to the colour formats specified in 6.1, 6.2, and
Where requirements of this International Standard and
6.3, monochrome continuous tone and binary DDES
TIFF 6.0 are in conflict, this International Standard shall
images are also supported. These images are similar to
take precedence.
their colour counterparts, except that their formats take
advantage of the reduced amount of data associated with
7.1.1 Overview
monochrome (single colour) and binary images.
A TIFF/IT file conveys image data for a single image or a
6.4.1 Monochrome continuous tone picture image (MP)
set of related images. The TIFF/IT structure includes a
data
short header, one or more Image File Directories (IFD),
and the image data associated with the IFDs. Image
A monochrome continuous tone picture image (MP)
parameters are encoded in tagged fields in the IFD. Fields
consists of a rectangular array of pixels. Each pixel is
that are not used to describe an image are omitted from its
represented by a single byte value indicating the varying
IFD. Each field is identified by its tag value rather than its
intensity of the single image colour at that pixel location.
position in the directory entry.
The intended effect is to reproduce the monochrome
continuous tone picture using various levels of the
7.1.2 Header
specified image colour.
A TIFF/IT file begins with an eight-byte image file header.
The monochrome continuous tone picture format is similar
to, though not identical to, a monochrome version of the
Bytes O-l : The pair of bytes at offset 0 of the file contains
colour continuous tone picture format with a single colour
the IS0 646 characters “11” (4949h) or “MM”
per pixel and is therefore not interleaved.
(4D4Dh). “II” signifies that the file is stored in
little-endian byte order. “MM” signifies that
6.4.2 Binary picture image (BP) data
the file is stored in big-endian byte order. A
writer may write either of the two byte orders.
A binary picture image (BP) consists of a rectangular array
A reader shall interpret both byte orders.
of pixels. Each pixel is represented by a single bit value
indicating that the pixel location is to be part of the
NOTE 9 In normal TIFF usage, this parameter applies to all data
background (bit value 0) or part of the image (bit value 1)
within headers , directories, and image data. In this International
for that pixel location. The bits are ordered left to right Standard, certain 16-bit fields in the image data have a fixed “big-
endian” byte order which will be defined with the specific image
within the byte; i.e. the most significant bit first. A
data types in clause 7.3 through 7.8.
background and a foreground colour may each be
specified.
Bytes 2-3: The pair of bytes (SHORT) at offset 2 contains
the constant 42 (2Ah).
6.4.3 Binary line art image (BL) data
Bytes 4-7: The four bytes (LONG) at offset 4 contain the
A binary line art image (BL) consists of a rectangular array
offset of the first IFD of the file. The directory
of pixels. Each pixel is represented by a single value which
is required to begin on a word-aligned
is encoded as a sequence of pairs of background and image
boundary.
colours.
7.1.3 Image subfiles
The binary line art image is further characterized by having
continuous areas of many pixels of image and background
A TIFF/IT file contains one or more subfiles, each
colour. Run length encoding techniques are used.
representing a single image which may be among a set of
related images in the same TIFF/IT file. Each subfile
consists of an Image File Directory (In>) together with one
7 Requirements
or more referenced word-aligned sequences containing
image data.
The format of the TIFF/IT and TIFF/IT-PI image data files
and the specific requirements for each of the individual
image file types follow. See annex F for examples of the
structure of these files.
IS0 12639:1998(E)
0 IS0
The offsets of the word-aligned sequences containing the
7.1.4 PFD (Image File Directory)
image data for each strip are contained in the data values of
Each IFD is located at an arbitrary word-aligned offset the mandatory StripOffsets field (tag 273, LONG or
within the file. The IFDs are forward-chained together. SHORT, count = StripsPerlmage) .
An IFD consists of a two-byte count of the quantity of IFD
entries within it, one or more IFD entries sorted in The StripByteCounts field (tag 279, LONG or SHORT,
ascending order of tag number, and a four-byte offset to the Count = StripsPerlmage) specifies the number of bytes for
each strip.
next IFD in the chain (zero in the case of the last IFD in the
file). Each IFD entry is a 12-byte field, describing a one-
parameter field that defines an attribute of the file. The structure of a TIFF/IT file containing a single image
subfile is shown in figure 1.
7.1.5 IFD entry
7.2 General parameters
Each IFD entry consists of a SHORT (two-byte) tag
number identifying the field, a SHORT (two-byte) data
This subclause describes, in general terms, each of the
type identifying the field type, a LONG (four-byte) count, fields used in TIFF/IT files. For usage specific to an image
and a LONG (four-byte) offset value. The offset value
file type (i.e. CT, LW, HC, MP, BP, and BL) see the
shall be an even number since the value is expected to be
subclause appropriate to that file type. Annex H provides
on a 16-bit word boundary.
an alphabetical listing of TIFF/IT fields.
The field type codes are: 7.2.1 Job identification
1 BYTE
The job and picture name of the image are described by the
2 ASCII
document name (DocumentName) and image description
3 SHORT
(ImageDescription) fields. The page name (PageName)
4 LONG
field may also be used. Annex H contains an alphabetical
5 RATIONAL
list of TIFF/IT fields.
The count determines the number of data elements in the 269 DocumentName ASCII [Job Name]
value. The count of an ASCII string entry shall be the 270 ImageDescription ASCII [Picture Name, Image
number of characters (bytes) in the string, including the Name]
terminating null character.
285 PageName ASCII
NOTE 10 In the case of an ASCII string, the IS0 10755, IS0
The originator of the image may be identified, and a
10756, and IS0 10759 headers do not have a terminating null,
copyright statement may be included using the Artist and
and so these field sizes are one less than a corresponding TIFF/IT
Copyright fields, respectively.
count with the appended null character.
315 Artist ASCII
33432 Copyright ASCII
The data value associated with an IFD entry is stored
directly in the offset value field of the IFD entry, if its type
7.2.2 System identification
and count combine to indicate a length of four bytes or less.
Otherwise, the offset value field of the IFD entry contains
The following fields may be used to describe system data
the offset of a referenced, word-aligned sequence that
relating to the image:
contains the indicated count of data elements.
271 Make ASCII [Vendor Name]
7.1.6 Image data
ASCII
272 Model
305 Software ASCII [Program Name]
Image data is stored in one or more word-aligned
306 DateTime ASCII
sequences. The array of pixels making up the image may
HostComputer ASCII
be divided into strips. Each strip of an image, except
34016 Site ASCII [Site Name]
possibly the last strip, contains the number of rows
ASCII
340 18 IT8Header
specified in the RowsPerStrip field (tag 278, SHORT or
LONG, default FFFFFFFFh). If RowsPerStrip equals or
It is recommended to include the three-character country
exceeds ImageLength, as is the default, then the entire
code from IS0 3 166 as the last three characters, before the
image is contained within a single strip. Each strip is held
terminating “null” character, of the Make field, to identify
in a single word-aligned sequence of data.
the country of registry of the vendor name.
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IS0 12639:1998(E)
TIFF/IT
lmaqe File Header
.
Directory Entry
Byte Order
X
Version Taq .
Xt2
Offset of Type
0th IFD
x+4 I I - I I I -
Count
X+8 Offset
1-1 Y m-1
Value
IFD
Entry Count
B
A
A+2 Directory Entry 0
Directory Entry I
A+14
A+26 Directory Entry 2
Directory Entry n
Y -1 Value
Tag 273
A+2+12B Offset of next IFD
Subfile
f
lmaqe Data
.
Z
Figure 1 - Structure of TIFF/IT file for single image subfile (single strip)
The Site field allows the identity of the location at which 256 ImageWidth SHORT or LONG [pixels
the image was digitized (or encoded into TIFF/IT) to be per line]
included with the file.
257 ImageLength SHORT or LONG [lines in
NOTE 11 The ITSHeader field provides the ability to include
image]
unmodified headers (appended by an ASCII “null” at the end of
274 Orientation SHORT
the character string) from IS0 10755, IS0 10756, and IS0 10759
in the TIFF/IT files. This may be particularly useful if a file is
Basic orientations are specified as follows (see figure 2):
being transported from one IS0 10755, IS0 10756, or IS0 10759
environment to another via TIFF/IT. TIFF/IT readers are not
1=
Load from top left, horizontally (default)
required to interpret and use the contents of the IT8Header field.
the 0th row represents the visual top of the image, and
the 0th column represents the visual left-hand side.
7.2.3 Image size and orientation
5 = Load from top left, vertically
Image size and orientation are defined by three fields. One
the 0th row represents the visual left-hand side of the
field specifies the width of an image, another specifies the
image, and the 0th column represents the visual top.
length of the image, and the third specifies the orientation
of the scan lines with respect to the image content as
4 = Load from bottom left, horizontally
viewed by the end user.
the 0th row represents the visual bottom of the image,

IS0 12639: 1998(E)
0 IS0
Basic
Orientations
5 8
Optional
Orientations
6 3 7
Arrow represents the sequence of the first line of pixels in the data stream
Figure 2 - Relationship between first line of data, image orientation, and orientation code.
(scanlines in image) fields refer to the sequence of pixels in the
and the 0th column represents the visual left-hand side.
data stream and not the logical image itself. The TIFF and
TIFF/IT term “Width” ( “length of line“ in IS0 10755, IS0 10756,
8 = Load from bottom left, vertically
or IS0 10759) refers to the dimension of the image represented by
the 0th row represents the visual left-hand side of the
the first line of pixels in the data stream. The TIFF and TIFF/IT
image, and the 0th column represents the visual
term “Length” ( “breadth of area” in IS0 10755, IS0 10756, or
bottom.
IS0 10759) refers td the dimension of the image represented by
the number of lines in the data stream. For example, orientations
Conformance to this International Standard requires that at
” 1” and “4” define “Width” as the horizontal axis of the logical
least one basic orientation be written and all four basic
image, and “Length” as the vertical axis. Orientations “5” and “8”
orientations be read.
define “Width” as the vertical axis and “Length” as the horizontal
axis.
Optional orientations are specified as follows (see figure
.
7.2.4 Image resolution
.
2)
282 XResolution RATIONAL [resolution of line]
2 = Load from top right, horizontally
283 YResolution RATIONAL [resolution of
the 0th row represents the visual top of the image, and
breadth]
the 0th column represents the right-hand side.
296 ResolutionUnit SHORT
6= Load from top right, vertically
The resolution (number of pixels per ResolutionUnit) may
the 0th row represents the visual right-hand side of the
be specified in both the Width (line) and Length (breadth)
image, and the 0th column represents the visual top.
directions. The values for ResolutionUnit for TIFF/IT and
TIFF/IT-PI conformity levels shall be centimetres
3= Load from bottom right, horizontally
represented by value 3 and inches represented by value 2
the 0th row represents the visual bottom of the image,
(default value) in field 296. The other value recognized by
and the 0th column represents the visual right-hand
TIFF, but not by TIFF/IT, is 1, meaning no absolute unit of
side.
measurement is specified.
7= Load from bottom right, vertically
Pixels do not need to be square in size. To properly size an
the 0th row represents the visual right-hand side of the
image, the resolution of both axes must be considered. The
image, and the 0th column represents the visual
necessary information is provided by the resolution
bottom.
specifications for each axis, and the number of pixels for
NOTE 12 IS0 10755, IS0 10756, and IS0 10759 made
each axis. From this, the size of each axis may be
provision for unknown orientations; TIFF/IT does not.
determined by dividing the number of pixels by the
resolution.
NOTE 13 The size, resolution, and orientation fields interact to
describe the size and orientation of the logical image in the data
stream. The ImageWidth (pixels per scanline) and ImageLength
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IS0 12639:1998(E)
Table 1
- Encoding of data format
File Type SamplesPerPixel
BitsPerSample Compression PlanarConfiguration
Colour continuous tone picture 1-16 8, 8, . . . 1 or 32895 1
(CT) - pixel interleaved
Colour continuous tone picture 1-16 8, 8, . . . 1 or 32895 32768
(CT) - line interleaved
Colour continuous tone picture 1-16 8, 8, . . . 1 or 32895 2
(CT) - colour interleaved
Colour line art (LW) 1 8 32896 omit, not used
High resolution continuous tone 2 -16 8, 8, . . . 32897 1
even values only
WC)
Monochrome continuous tone 1 8 1 or 32895 omit, not used
picture (MP)
Binary picture (BP) 1 1 1 omit, not used
Binary line art (BL) 1 1 32898 omit, not used
7.2.5 Data format the run length encoding scheme for the BL format
(value 32898)
The data format parameters describe the style and order of
the data stream. A number of TIFF/IT fields are used to PlanarConfiguration distinguishes between CT formats that
are pixel (sometimes referred to as “chunky ”), line or
encode them.
colour (i.e. colour plane or separation) interleaved, by
254 NewSubfileType LONG values 1, 32768, and 2 respectively. The value defaults to
1, and the field may be omitted when SamplesPerPixel
NewSubfileType is a general indication of the kind of data equals 1.
contained in the subfile. The value is made up of 32 flag
bits. Unused bits shall be 0. Bit 0 is the low-order bit. Table 1 summarizes how the data formats for the different
file types are encoded by these TIFF/IT fields.
258 BitsPerSample SHORT
259 Compression SHORT 340 19 RasterPadding SHORT
277 SamplesPerPixel SHORT
284 Planarconfiguration SHORT The RasterPadding field allows each line of colour or
interleaved colours to be padded to a 1-, 2-, 4-, 5 12-, or
The fields SamplesPerPixel and BitsPerSample determine 1024-byte boundary.
the number of samples (separations, colours) and their size.
This information, with that provided in the fields 0 = byte raster (default value) - pad to 1 byte
Compression and PlanarConfiguration, determine the 1 = word raster - pad to 2 bytes
format of the data in the file. The count of BitsPerSample 2 = long word raster - pad to 4 bytes
9 = sector raster - pad to 5 12 bytes
data elements shall equal the value of the SamplesPerPixel
10 = long sector raster - pad to 1024 bytes
fields.
When applied to line interleaved data, this field relates to
If the value of Compression is the default value of “l”,
each line of colour, rather than to each line of pixels. The
there is no compression. (The BP data format packs data
value of the field is the power of two corresponding to the
into bytes as tightly as possible, with no unused bits except
at the end of a row.) The other TIFF/IT values of the padding length (in bytes).
compression indicate:
Two additional fields are required for the TIFF/IT-LW line
the use of RasterPadding in the CT or MP format art files. They describe the number of bits required to
describe short and long runs. See the individual file type
(value 32895)
for more information.
the run length encoding scheme for the LW format
(value 32896)
34020 BitsPerRunLength SHORT (default = 8)
the run length encoding scheme for the HC format
3402 1 BitsPerExtendedRunLength SHORT (default = 16)
(value 32897)
IS0 12639: 1998(E)
0 IS0
The HC file has specific usages which determine the type 7.2.7.2 Colour sequence
of information contained within the file. HCUsage is an
indicator of the type of information contained within the
262 PhotometricInterpretation SHORT (=5 for
HC file.
separations)
340 17 ColorSequence ASCII [Sequence of
34030 HCUsage
LONG Colours ]
The bits of HCUsage indicate the type of information Value 5 for PhotometricInterpretation for CT, LW, and HC
contained in the HC file. If all bits are 0, or the field is not images signifies separated image file data in the sequence
present, the information type is unknown. Each bit
CMYK, or a separated image file data in other colours or
indicates a type of information which may be coded in the
sequences if modified by other fields. Values 0 and 1 are
file, the bits are not mutually exclusive since an HC file used for MP, BP, and BL images.
may contain both contone and line art information:
This International Standard provides for two basic colour
bit 0: 1 means the file contains high resolution CT sequences describing four-colour separations. These basic
contone information colour sequences are specified by values “CMYK” and
bit 1: 1 means the file contains line art (line work) “YMCK” in the ColorSequence field.
information
bit 2: 1 means the file contains trapping information To specify optional colours or colour sequences in this
bit 3-3 1: Reserved, must contain zeroes International Standard, the following entries in the
ColorSequence field may be used in any sequence (colour
7.2.6 File format entries may be repeated for additional separations of the
same colour):
Many prepress applications use only one strip in the
IIYII "M" "Cll "K" =
TIFF/IT formats. In these cases, there will be only one Yellow, magenta, cyan, and black
strip offset and byte count, and the RowsPerStrip field may inks
“R” IIG” IIB 11
be omitted. In other cases, the usage of StripOffsets, = Red, green, blue light intensity
“U” yt “L”
RowsPerStrip, and StripByteCounts fields are as described = CIE 1976 projective u ’, v ’, and
in TIFF 6.0, Part 1: Baseline.
photopic luminance (Y)
” 1 ” to “9” = User-definable colours or
S tripoffsets
273 LONG or SHORT separations; such as pink, varnish,
278 RowsPerStrip LONG or SHORT etc.
11 11
279 S tripByteCounts LONG or SHORT = Present in the data stream but ignored
Q
See 7.1.6 for the use of these parameters. The use of ColorSequence for RGB images is discouraged.
The TIFF 6.0 specification, Section 6: RGB Full Colour
7.2.7 Colour specification Images, should be used unless TIFF/IT specific features
and functionality is required for RGB images.
The primary colour space for this International Standard is
CMYK, with other colour spaces provided for as described NOTE 14 The “Sequence of Colours” field in IS0 10755, IS0
10756, and IS0 10759 is fixed-length and space-padded: the
below. The parameters for specifying the colour space are:
TIFF/IT ColorSequence field is variable-length and null-
terminated.
- the number of colour separations,
- the colour sequence,
NOTE 15 Other colour sequences for red, green, blue are
- the colour values.
unlikely to be found. UVL is also unlikely to be found. They are
retained only for backward compatibility with IS0 10755 and IS0
7.2.7.1 Number of colour separati
...