ISO 15076-1:2005

Image technology colour management - Architecture, profile format and data structure - Part 1: Based on ICC.1:2004-10

ISO 15076-1:2005 specifies a colour profile format and describes the architecture within which it can operate. This supports the exchange of information which specifies the intended colour image processing of digital data. Specification of the required reference colour spaces and the data structures (tags) are included.

Gestion de couleur en technologie d'image — Architecture, format de profil et structure de données — Partie 1: Sur la base de l'ICC.1:2004-10

General Information

• Status: Withdrawn
• Publication Date: 23-Nov-2005
• Withdrawal Date: 23-Nov-2005
• ICS: 37.100.99 - Other standards related to graphic technology
• Technical Committee: ISO/TC 130 - Graphic technology
• Drafting Committee: ISO/TC 130/JWG 7 - Joint TC 130 - ICC WG: colour management
• Parallel Committee: ISO/TC 42 - Photography
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 26-Nov-2010
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 15076-1:2010 - Image technology colour management - Architecture, profile format and data structure - Part 1: Based on ICC.1:2010
• Effective Date: 04-Jul-2009

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 15076-1
First edition
2005-12-01
Image technology colour management —
Architecture, profile format and data
structure —
Part 1:
Based on ICC.1:2004-10
Gestion de couleur en technologie d'image — Architecture, format de
profil et structure de données —
Partie 1: Sur la base de l'ICC.1:2004-10

Reference number
©
ISO 2005
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2005
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 either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2005 – All rights reserved

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 15076-1 was prepared by the International Color Consortium, in cooperation with Technical Committees
ISO/TC 130 Graphic technology and ISO/TC42 Photography, under the provisions of the Cooperative
Agreement between ISO/TC130 and the International Color Consortium dated 2003-07-11.
ISO 15076-1 is technically identical to ICC.1:2004-10, Image technology colour management — Architecture,
profile format, and data structure (Profile version 4.2.0.0).
ISO 15076 consists of the following parts, under the general title Image technology colour management —
Architecture, profile format, and data structure.
— Part 1: Based on ICC.1:2004-10
Contents Page
Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
1  Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2  Compliance and registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
3  Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
4  Terms and definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
5  Basic numeric types and abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5.1  Basic number types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5.2  Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6  Profile Connection Space and rendering intents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.1  Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.2  Rendering intents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.3  Profile Connection Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.4  Converting between CIEXYZ and CIELAB encodings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7  Profile requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7.1  General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7.2  Profile header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.3  Tag table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7.4  Tag data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
8  Required tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
8.1  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
8.2  Common requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.3  Input profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.4  Display profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
8.5  Output profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
8.6  DeviceLink profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
8.7  ColorSpace conversion profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.8  Abstract profile. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.9  Named colour profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.10  Priority of tag usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
9  Tag definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
9.1  General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
9.2  Tag listing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
10  Tag type definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.1  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.2  chromaticityType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
10.3  colorantOrderType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
10.4  colorantTableType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
10.5  curveType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
10.6  dataType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
10.7  dateTimeType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
10.8  lut16Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
10.9  lut8Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
10.10  lutAtoBType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
10.11  lutBtoAType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
10.12  measurementType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
10.13  multiLocalizedUnicodeType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
10.14  namedColor2Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
10.15  parametricCurveType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
iv © ISO 2005 – All rights reserved

10.16  profileSequenceDescType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
10.17  responseCurveSet16Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
10.18  s15Fixed16ArrayType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
10.19  signatureType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
10.20  textType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
10.21  u16Fixed16ArrayType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
10.22  uInt16ArrayType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
10.23  uInt32ArrayType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
10.24  uInt64ArrayType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
10.25  uInt8ArrayType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
10.26  viewingConditionsType. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
10.27  XYZType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Annex A (informative) Colour spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Annex B (normative) Embedding profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Annex C (informative) Relationship between ICC profiles and PostScript CSAs and CRDs . . . . . . . . 71
Annex D (informative) Profile Connection Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Annex E (informative) Chromatic adaptation tag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Annex F (normative) Profile computational models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Annex G (informative) Tables of required tags and tag list. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Introduction
0.1 General ®
This International Standard specifies the profile format defined by the International Color Consortium (ICC).
The intent of this format is to provide a cross-platform device profile format. Such device profiles can be used to
translate colour data created on one device into another device’s native colour space. The acceptance of this
format by operating system vendors allows end users to transparently move profiles and images with
embedded profiles between different operating systems. For example, this allows a printer manufacturer to
create a single profile for multiple operating systems.
It is assumed that the reader has a nominal understanding of colour science, such as familiarity with the
CIELAB colour space, general knowledge of device characterizations, and familiarity with at least one
operating system level colour management system.
0.2 International Color Consortium
The International Color Consortium was formed with the primary intent of developing and administering a
profile format standard, and for the registration of tag signatures and descriptions. The founding members of
this consortium were: Adobe Systems Inc., Agfa-Gevaert N.V., Apple Computer, Inc., Eastman Kodak
Company, FOGRA (Honorary), Microsoft Corporation, Silicon Graphics, Inc., Sun Microsystems, Inc., and
Taligent, Inc. These companies committed to fully support the standard in their operating systems, platforms
and applications. The consortium has since been expanded and now has over 60 members.
The initial version of the standard developed by the consortium has undergone various revisions and it was
agreed by ICC that its revision 4.2 should be proposed as an International Standard. It is that revision which
has formed the basis of this International Standard. The ICC will continue to administer its own version of the
document and, if enhancements are made, they will be seriously considered for future revisions of this
International Standard. ISO TC130 will work to ensure that there are no significant differences between the ICC
and ISO versions of the document.
The ICC web site (www.color.org) provides supplementary information relevant to this International Standard
and additional resources for developers and users. It also provides information on how to become a member of
ICC.
0.3 Colour Management Architecture and Profile Connection Space
The underlying architecture assumed in this International Standard is based around a reference colour space
that is unambiguously defined. The colour specification method selected was that defined by CIE which is
internationally accepted. The CIE system enables a set of tristimulus values (XYZ) to be specified for a
coloured stimulus. These tristimulus values enable a user to determine whether colours match, and the degree
of mis-match between any that do not. It follows that it is possible to define the colour of a sample by these
tristimulus values (or some defined transformation of them) for matching by colour reproduction.
Calculation of the XYZ values for transmitting or reflecting media is achieved from the spectral sum-product of
the reflectance or transmittance of the sample, the relative spectral power distribution of the illuminant used to
view it and the 'sensitivity' of the standard observer. However, as CIE defines two standard observers, two
measurement geometries (for reflecting media) and a large number of illuminants, it is necessary to restrict
these options in order to have a system that is not ambiguous for a particular application. For this International
Standard ICC have defined such a restriction, based on ISO 13655:1996, Graphic Technology - Spectral
measurement and colorimetric calculation for graphic arts images, and the resultant colour space is known as
the Profile Connection Space (PCS). Furthermore, the simple CIE system (whether XYZ or the CIELAB values
derived from them) does not accommodate the effect of surrounding stimuli to the sample being measured
(which can be different for various types of media) or the level of illumination. Both of these affect appearance
so the PCS values do not by themselves specify appearance. To overcome this problem the PCS is used in two
different ways. The first simply describes the colorimetry of actual originals and their reproductions through the
colorimetric rendering intents. The second, which describes the colorimetry of an image colour rendered to a
vi © ISO 2005 – All rights reserved

standard reference medium under a specified viewing condition, is employed for the perceptual rendering
intent. Thus it may incorporate corrections for appearance, and other desired rendering effects, as well as
accommodating differences between the device and the reference PCS dynamic range. When required the
viewing conditions may be specified to allow appearance to be determined for the colorimetric rendering
intents.
So, in summary, the PCS is based on XYZ (or CIELAB) determined for a specific observer (CIE Standard 1931
Colorimetric Observer - often known colloquially as the 2 degree observer), relative to a specific illuminant (D50
- a chromatic adaptation transform is used if necessary), and measured with a specified measurement
o o o o
geometry (0 /45 or 45 /0 ), for reflecting media. Measurement procedures are also defined for transmitting
media. (Since the conversion from XYZ to CIELAB is quite unambiguous profile builders can use either, and the
application is able to determine which has been used from a tag in the header).
For colorimetric renderings, where the measured data was not made relative to D50 the profile builder is
expected to correct the data to achieve this. However a mechanism for identifying the chromatic adaptation
used in such situations is provided. For the perceptual rendering intent the same viewing conditions are
assumed, but an additional constraint is added in that a reference medium and illumination level is specified in
order to provide a more robust mechanism for describing colour rendering (including gamut mapping). In the
following paragraphs the reference colour space referred to should be taken to include the viewing conditions
and reference medium when the perceptual intent is being considered. For the perceptual rendering intent
profile builders are expected to undertake any corrections for appearance effects if the viewing conditions used
for monitors and transmitting media (such as dark surrounds) differ from those typical for reflecting media.
Figure 1 shows how a reference colour space can be used to provide the common interface for colour
specification between devices. Without it a separate transformation would be required for each pair of devices.
If there are n devices in a system, and it is necessary to provide a transformation between each device and
every other device, n transforms would need to be defined and n new transforms would need to be defined
every time a new device is added. By use of a reference colour space only n transforms need be defined and
only one new transform needs to be defined each time a new device is added.
Figure 1 — Use of a reference colour space
While images could be encoded directly in the reference colour space defined by the PCS this will not generally
be the case. For precision reasons it is usually desirable to define the transformation between the device colour
space and the PCS at a higher precision than the bit-depth of the image. So, the transformation between a
device colour space and the PCS is usually defined at high precision. If this transformation is provided with any
image file appropriate to that device it can be utilised when images are reproduced. By combining the profiles
for the pair of devices for which image reproduction is required, using the common PCS as the interface as
shown in Figure 1, appropriate colour reproduction is assured with a minimal loss of precision. In order that the
transformation between the device colour space and the PCS can be interpreted by all applications it is
important that it be defined in an open specification. The profile format defined in this International Standard
provides that specification.
0.4 Rendering intents
In general, actual device colour gamuts will fail to match each other, and that of the reference medium, to
varying degrees. Because of this mismatch, and because of the needs of different applications, four rendering
intents (colour rendering styles) are defined in this specification. Each one represents a different colour
reproduction compromise. The colorimetric rendering intents operate directly on measured colorimetric values,
though possibly with correction for chromatic adaptation when the measured values were not calculated for the
D50 PCS illuminant. The other rendering intents (perceptual and saturation) operate on colorimetric values
which are corrected in an as-needed fashion to account for any differences between devices, media, and
viewing conditions.
Two colorimetric rendering intents are specified in this International Standard, though only one is directly
defined in the profile. The defined colorimetric intent (media-relative colorimetric intent) is based on media-
relative colorimetry in which data is normalised relative to the media white point for reflecting and transmitting
media. (Thus the media white will have the PCS CIELAB values (100, 0, 0)). However, because the profile is
also required to contain the PCS values of the media white, relative to the perfect reflecting diffuser or
transmitter under D50, it is possible for all the media-relative values to be re-calculated relative to these. When
this is done the resultant rendering intent is known as the absolute colorimetric intent. The use of media-relative
colorimetry enables colour reproductions to be defined which maintain highlight detail, while keeping the
medium ‘white’, even when the original and reproduction media differ in colour. However, this procedure
inevitably introduces some change in all colours in the reproduction. When an exact colour match is required
for all within gamut colours the absolute colorimetric rendering intent will define this.
The colour rendering of the perceptual and saturation rendering intents is vendor specific. The former, which is
useful for general reproduction of pictorial images, typically includes tone scale adjustments to map the
dynamic range of one medium to that of another, and gamut warping to deal with gamut mismatches. The
latter, which is useful for images which contain objects such as charts or diagrams, usually involves
compromises such as trading off preservation of hue in order to preserve the vividness of pure colours.
For perceptual transforms it is desirable, in order to optimise colour rendering, to place some bounds on the
colour gamut of the PCS values. For this reason a reference medium and reference viewing condition have
been defined which apply only to the perceptual rendering. The reference medium is defined as a hypothetical
print on a substrate with a white having a neutral reflectance of 89%, and a density range of 2,4593. The
reference viewing condition is the P2 condition specified in ISO 3664 - Viewing conditions - for Photography
and Graphic Technology, i.e. D50 at 500 lux for viewing reflecting media. A neutral surround, of 20%
reflectance is assumed.
The choice of a reference medium with a realistic black point for the perceptual intent provides a well-defined
aim when tonal remapping is required. Inputs with a dynamic range greater than a reflection print (for example,
a slide film image, or the colorimetry of high-range scenes) can have their highlights and shadows smoothly
compressed to the range of the print in such a way that these regions can be expanded again without undue
loss of detail on output to wide-range media. Likewise, images from original media with limited dynamic range
can be colour rendered to the expanded dynamic range of the reference medium, in order to ensure
interoperability.
Profiles generally offer more than one transformation, each of which is applicable to a specific rendering intent.
When the intent is selected the appropriate transformation is selected by the colour management application.
The choice of rendering intent is highly dependent upon the intended use. In general the peceptual rendering
intent is most applicable for the rendering of natural images, though not always. In particular, in a proofing
environment - where the colour reproduction obtained on one device is simulated on another - colorimetric
rendering is most appropriate.
viii © ISO 2005 – All rights reserved

For those requiring further information an extended discussion of many of the issues described above is
provided in Annex D.
0.5 Device profiles
Device profiles provide colour management systems with the information necessary to convert colour data
between native device colour spaces and device independent colour spaces. This International Standard
divides colour devices into three broad classifications: input devices, display devices and output devices. For
each device class, a series of base algorithmic models are described which perform the transformation
between colour spaces. Figures 2 and 3 show examples of these models, which provide a range of colour
Figure 2 — The different ways of converting a colour from PCS to device space. (a) Matrix/TRC model
(b)-(e) The four different ways of applying a lutBtoAType table. Only (d) and (e) can be used if the device
space has more than 3 components/colour.
Figure 3 — Examples of converting a colour from device to PCS. (a) Matrix/TRC model (b)-(e) The four
different ways of applying a lutAtoBType table. Only (d) and (e) can be used if the device space has
more than 3 components/colour.
quality and performance results. Each of the base models provides different trade-offs in memory footprint,
performance and image quality. The necessary parameter data to implement these models is described in the
appropriate tag type descriptions in clause 10. This required data provides the information for the colour
management framework default colour management module (CMM) to transform colour information between
native device colour spaces. A representative architecture using these components is illustrated in Figure 4.
x © ISO 2005 – All rights reserved

.
Figure 4 — Colour management architecture
0.6 Profile element structure
The profile structure is defined as a header followed by a tag table followed by a series of tagged elements that
can be accessed randomly and individually. This collection of tagged elements provides three levels of
information for developers: required data, optional data and private data. An element tag table provides a table
of contents for the tagging information in each individual profile. This table includes a tag signature, the
beginning address offset and size of the data for each individual tagged element. Signatures in this
International Standard are defined as a four-byte hexadecimal number. This tagging scheme allows developers
to read in the element tag table and then randomly access and load into memory only the information
necessary to their particular software application. Since some instances of profiles can be quite large, this
provides significant savings in performance and memory. The detailed descriptions of the tags, along with their
intent, are included later in this International Standard.
The required tags provide the complete set of information necessary for the default CMM to translate colour
information between the Profile Connection Space and the native device space. Each profile class determines
which combination of tags is required.
In addition to the required tags for each device profile, a number of optional tags are defined that can be used
for enhanced colour transformations. Examples of these tags include PostScript Level 2 support, calibration
support, and others. In the case of required and optional tags, all of the signatures, an algorithmic description
(where appropriate), and intent are registered with the International Color Consortium. Private data tags allow
CMM developers to add proprietary value to their profiles. By registering just the tag signature and tag type
signature, developers are assured of maintaining their proprietary advantages while maintaining compatibility
with this International Standard. However, since the overall philosophy of this format is to maintain an open,
cross-platform standard, developers are encouraged to keep the use of private tags to an absolute minimum.
0.7 Embedded profiles
In addition to providing a cross-platform standard for the actual disk-based profile format, this International
Standard also describes the convention for embedding these profiles within graphics documents and images.
Embedded profiles allow users to transparently move colour data between different computers, networks and
even operating systems without having to worry if the necessary profiles are present on the destination
systems. The intention of embedded profiles is to allow the interpretation of the associated colour data.
Embedding specifications are described in Annex B of this document.
0.8 Other profiles
Four profile types, in addition to the device profile types described above, are defined in this specification.
DeviceLink profiles provide a dedicated transformation from one device space to another, which can be useful
in situations where such a transformation is used frequently or has required optimisation to achieve specific
objectives. (Figure 5 shows the various algorithmic models which may be used to construct a DeviceLink
profile.).
“B”curves
Output Device Space
Input Device Space
⎡ ⎤
⎡ ⎤
Channel 1
Channel 1
⎢ ⎥
⎢ ⎥
Channel 2
Channel 2
⎢ ⎥
⎢ ⎥
⎢ . ⎥
⎢ . ⎥
.
⎣ ⎦ .
⎣ ⎦
.
.
Channel n
Channel n
.
.
.
(a)
“B”curves
”M”curves
Input Device Space
Output Device Space
⎡ ⎤ ⎡ ⎤
Channel 1 Channel 1
⎣ ⎦ ⎣ ⎦
Channel 2 Matrix Channel 2
3×4
Channel 3 Channel 3
(b)
“A” curves
“B”curves
Output Device Space
Multi-dimensional
Input Device Space
lookup table
⎡ ⎤
⎡ ⎤
Channel 1
Channel 1
⎢ ⎥
⎢ ⎥ Channel 2
Channel 2
⎢ ⎥
⎢ ⎥
⎢ ⎥
⎢ ⎥ CLUT .
.
. .
⎣ ⎦
⎣ ⎦ .
.
Channel n Channel m
.
.
.
.
.
.
(c)
“A”curves
“B”curves
”M”curves Output Device Space
Multi-dimensional
Input Device Space lookup table
⎡ ⎤
Channel 1 ⎡ ⎤
Channel 1
⎢ ⎥
Channel 2
⎢ ⎥
Matrix ⎣ ⎦
CLUT 3×4 Channel 2
⎢ ⎥
.
.
⎣ ⎦
.
Channel 3
Channel n
.
.
.
(d)
Figure 5 — Examples of converting a colour from device to device using a DeviceLink profile. (a) TRC
model (b) Matrix/TRC model (c) CLUT, plus TRC model (d) CLUT, plus matrix, plus CRT model. Only (a),
(c) and (d) can be used if the device space has more than 3 components/colour.
ColorSpace conversion profiles provide a transformation between a non-device colour space and the PCS,
which can prove useful in workflows in which reference colour spaces different from those selected by ICC are
utilised. Abstract profiles are defined from PCS to PCS and enable colour transformations to be defined that
xii © ISO 2005 – All rights reserved

provide some specific colour effects. Named Colour profiles provide a mechanism for specifying the
relationship between device values and the PCS for specific colours, rather than for general images
0.9 Organizational description of this International Standard
This International Standard addresses a very complex set of issues and the organization of this document
strives to provide a clear, clean, and unambiguous explanation of the entire format. To accomplish this, the
overall presentation is from a top-down perspective, beginning with the summary overview presented above,
followed by the necessary background information and definitions needed for unambiguous interpretation of
the text. A description of the Profile Connection Space and Rendering Intents is then provided before
continuing down at increasing levels of detail into a byte stream description of the format. Clause 6 describes
the Profile Connection Space and Rendering Intents; clause 7 describes the structure of the various fields
required in a profile; and clause 8 describes the content of the required tags for each profile class. Clause 9
lists the various tag types (optional and required) and briefly summarises the function of the tag as well as
listing the signature and allowed tag types for each. The tag types are defined in clause 10. Annex A provides
additional information pertaining to the colour spaces and rendering intents used in this International Standard
while Annex B provides the necessary details to embed profiles into PICT, EPS, TIFF, and JFIF files. Annex C
provides a general description of the PostScript Level 2 tags used in this International Standard while Annex D
provides some background material on the Profile Connection Space. Annex E provides additional information
pertaining to Chromatic Adaptation and the chromaticAdaptationTag while Annex F describes some the
computational models assumed in this International Standard. Annex G summarises in tabular form the
required tags for each profile class as specified in clause 8.
0.10 Patent statement
The International Organization for Standardization (ISO) draws attention to the fact that it is claimed that
compliance with this document may involve the use of a patent concerning the outputResponseTag, (support of
the outputResponseTag is optional), given in subclause 9.2.27. ISO takes no position concerning the evidence,
validity and scope of this patent right. Eastman Kodak Company, the holder of this patent right has assured the
ISO that he/she is willing to negotiate licences under reasonable and non-discriminatory terms and conditions
with applicants throughout the world. In this respect, the statement of the holder of this patent right is registered
with ISO. Information may be obtained from Eastman Kodak Company, 343 State street, Rochester, NY 14650.
INTERNATIONAL STANDARD ISO 15076-1:2005(E)

Image technology colour management — Architecture, profile
format and data structure —
Part 1:
Based on ICC.1:2004-10
1  Scope
This part of ISO 15076 specifies a colour profile format and describes the architecture within which it can
operate. This supports the exchange of information which specifies the intended colour image processing of
digital data. Specification of the required reference colour spaces and the data structures (tags) are included.
NOTE The technical content of this document is identical to that of ICC.1:2004-10.
2  Compliance and registration
Any colour management system, application, utility or device driver that claims conformance with this
specification shall have the ability to read the profiles as they are defined in this specification. Any profile-
generating software and/or hardware that claims conformance with this specification shall have the ability to
create profiles as they are defined in this specification. ICC conforming software shall use the ICC profiles in an
appropriate manner.
This specification requires that signatures for CMM type, device manufacturer, device model, profile tags and
profile tag types shall be registered to insure that all profile data is uniquely defined. The registration authority
for these data is the ICC Technical Secretary.
NOTE See the ICC Web Site (www.color.org) for contact information.
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.
ISO 5-3:1995, Photography — Density measurements — Part 3: Spectral conditions
ISO 639-1:2002, Codes for the representation of names of languages — Part 1: Alpha-2 code
ISO/IEC 646:1991, Information technology — ISO 7-bit coded character set for information interchange
ISO 3166-1:1997, Codes for the representation of names of countries and their subdivisions — Part 1: Country
codes
ISO 3664:2000, Viewing conditions — Graphic Technology and Photography
ISO 13655:1996, Graphic technology — Spectral measurement and colorimetric computation for graphic arts
images
IEC 61966-2-1 (1999-10), Multimedia systems and equipment — Colour measurement and management —
Part 2-1: Colour management — Default RGB colour space — sRGB
IEC 61966-3 (2000-03), Multimedia systems and equipment — Colour measurement and management — Part
3: Equipment using cathode ray tubes
DIN 16536-2:1995, Testing of prints and printing inks in graphic technology — Colour density measurements
on on-press or off-press prints — Part 2: Instrument specifications for reflection densitometers and their
calibration
EBU Tech. 3213-E: EBU standard for chromaticity tolerances for studio monitors
ITU-R BT.709-2, Parameter values for the HDTV standards for production and international programme
exchange
SMPTE RP 145-1994: SMPTE C Color Monitor Colorimetry
PICT Standard Specifications, Apple Computer, Inc.
PostScript Language Reference Manual, Third Edition, Adobe Systems Incorporated
TIFF 6.0 Specification, Adobe Systems Incorporated
Internet RFC 1321, The MD5 Message-Digest Algorithm, R. Rivest, April 1992, Available from Internet

4  Terms and definitions
For the purposes of this document, the following terms and definitions apply:
4.1
aligned
a data element is aligned with respect to a data type if the address of the data element is an integral multiple of
the number of bytes in the data type
4.2
ASCII text string
sequence of bytes, each containing a graphic character from ISO/IEC 646, the last character in the string being
a NULL (character 0/0)
4.3
big-endian
addressing the bytes within a 16, 32 or 64-bit value from the most significant to the least significant, as the byte
address increases
4.4
bit position
bits are numbered such that bit 0 is the least significant bit
4.5
byte
8-bit unsigned binary integer
4.6
byte offset
number of bytes from the beginning of a field
2 © ISO 2005 – All rights reserved

4.7
colour encoding
generic term for a quantized digital encoding of a colour space, encompassing both colour space encodings
and colour image encodings
[ISO 22028-1]
NOTE Values specified by an encoding are the closest representation to the colour space or image values permitted by
the encoding precision.
4.8
colour management (digital imaging)
communication of the associated data required for unambiguous interpretation of colour content data, and
application of colour data conversions, as required, to produce the intended reproductions
NOTE 1 Colour content may consist of text, line art, graphics, and pictorial images, in raster or vector form, all of which
may be colour managed.
NOTE 2 Colour management considers the characteristics of input and output devices in determining colour data
conversions for these devices.
4.9
fixed point
method of encoding a real number into binary by putting an implied binary point at a fixed bit position
NOTE Many of the tag types defined in this International Standard contain fixed point numbers. Several references can
be found (MetaFonts, etc.) illustrating the preferability of fixed point representation to pure floating point representation in
very structured circumstances.
4.10
hexadecimal
number system used to represent the value of a 4-bit binary word
NOTE The notation used to represent hexadecimal numbers in this International Standard is xxh.
4.11
NULL
character coded in position 0/0 of ISO/IEC 646
4.12
Profile Connection Space (PCS)
abstract colour space used to connect the source and destination profiles
NOTE See Annex D for a full description.
4.13
rendering intent
style of mapping colour values from one image description to another
NOTE See clause 6 and Annexes A and D for a description of the four rendering intents (ICC-absolute colorimetric,
relative colorimetric, perceptual and saturation) used in ICC profiles.
4.14
spot colour
single colorant, identified by name, whose printing tone-values are specified independently from the colour
values specified in a colour coordinate system
4.15
signature
alphanumerical 4-byte value, registered with the ICC
NOTE Shorter values are padded at the end with 20h bytes.
4.16
viewing flare
veiling glare that is observed in a viewing environment but not accounted for in radiometric measurements
made using a prescribed measurement geometry
[ISO 22028-1]
NOTE The viewing flare is expressed as a percentage of the luminance of adapted white.
4.17
veiling glare
light, reflected from an imaging medium, that has not been modulated by the means used to produce the image
[ISO 22028-1]
5  Basic numeric types and abbreviations
5.1  Basic number types
For the purposes of this document, the following basic numeric types are
...