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• Status: Withdrawn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
• Completion Date: 26-Nov-2010

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 15076-1:2005(E)
©
ISO 2005

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ISO 15076-1:2005(E)
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ISO 15076-1:2005(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 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
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ISO 15076-1:2005(E)
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
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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
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ISO 15076-1:2005(E)
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
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ISO 15076-1:2005(E)
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
2
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
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ISO 15076-1:2005(E)
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.
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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.
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ISO 15076-1:2005(E)
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.
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ISO 15076-1:2005(E)
.
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
...