SIST-TS ISO/TS 22028-4:2014
Photography and graphic technology - Extended colour encodings for digital image storage, manipulation and interchange - Part 4: European Colour Initiative RGB colour image encoding [eciRGB (2008)]
Photography and graphic technology - Extended colour encodings for digital image storage, manipulation and interchange - Part 4: European Colour Initiative RGB colour image encoding [eciRGB (2008)]
ISO/TS 22028-4:2012 defines an extended colour-gamut output-referred RGB colour image encoding designated as European Colour Initiative RGB [eciRGB (2008)]. Digital images encoded using eciRGB (2008) can be manipulated, stored, transmitted, displayed, or printed by digital still picture imaging systems. Two precision levels are defined, using 8 bits/channel and 16 bits/channel.
Photographie et technologie graphique - Codages par couleurs étendues pour stockage, manipulation et échange d'image numérique - Partie 4: Titre manque
Fotografija in grafična tehnologija - Razširjeno barvno kodiranje za shranjevanje, izmenjavo in ravnanje z digitalnimi slikami - 4. del: RGB po Evropski barvni pobudi za barvno kodiranje slik [eciRGB (2008)]
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Standards Content (Sample)
SLOVENSKI STANDARD
01-marec-2014
)RWRJUDILMDLQJUDILþQDWHKQRORJLMD5D]ãLUMHQREDUYQRNRGLUDQMH]DVKUDQMHYDQMH
L]PHQMDYRLQUDYQDQMH]GLJLWDOQLPLVOLNDPLGHO 5*%SR(YURSVNLEDUYQLSREXGL
]DEDUYQRNRGLUDQMHVOLN>HFL5*% @
Photography and graphic technology - Extended colour encodings for digital image
storage, manipulation and interchange - Part 4: European Colour Initiative RGB colour
image encoding [eciRGB (2008)]
Photographie et technologie graphique - Codages par couleurs étendues pour stockage,
manipulation et échange d'image numérique - Partie 4: Titre manque
Ta slovenski standard je istoveten z: ISO/TS 22028-4:2012
ICS:
01.070 Barvno kodiranje Colour coding
37.040.99 Drugi standardi v zvezi s Other standards related to
fotografijo photography
37.100.01 *UDILþQDWHKQRORJLMDQD Graphic technology in
VSORãQR general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL ISO/TS
SPECIFICATION 22028-4
First edition
2012-11-01
Photography and graphic
technology — Extended colour
encodings for digital image storage,
manipulation and interchange —
Part 4:
European Colour Initiative RGB colour
image encoding [eciRGB (2008)]
Photographie et technologie graphique — Codages par couleurs
étendues pour stockage, manipulation et échange d’image numérique —
Partie 4: Codage d’image en couleurs RGB par initiative de couleur
européenne [eciRGB(2008)]
Reference number
©
ISO 2012
© ISO 2012
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 copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 4
4.1 General . 4
4.2 Reference viewing environment . 5
4.3 Reference display . 6
4.4 eciRGB (2008) colour image encoding . 7
Annex A (informative) The eciRGB (2008) ICC profile considerations .11
Annex B (informative) Practical tolerances for viewing eciRGB (2008) encoded images .12
Annex C (informative) Comparison of primaries.15
Bibliography .17
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.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of document:
— an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical
experts in an ISO working group and is accepted for publication if it is approved by more than 50 %
of the members of the parent committee casting a vote;
— an ISO Technical Specification (ISO/TS) represents an agreement between the members of a
technical committee and is accepted for publication if it is approved by 2/3 of the members of the
committee casting a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for
a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or
ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be
transformed into an International Standard or be withdrawn.
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/TS 22028-4 was prepared by Technical Committee ISO/TC 42, Photography.
ISO/TS 22028 consists of the following parts, under the general title Photography and graphic
technology — Extended colour encodings for digital image storage, manipulation and interchange:
— Part 1: Architecture and requirements
— Part 2: Reference output medium metric RGB colour image encoding (ROMM RGB)
— Part 3: Reference input medium metric RGB colour image encoding (RIMM RGB) [Technical Specification]
— Part 4: European Colour Initiative RGB colour image encoding [eciRGB (2008)] [Technical Specification]
iv © ISO 2012 – All rights reserved
Introduction
This Technical Specification has been developed in order to meet the industry need for a complete,
fully documented, publicly available definition of an output-referred extended gamut RGB colour image
encoding which is optimized for an 8-bit encoding and the conversion of RGB images into offset print
colour spaces. Since users have also asked for a 16-bit encoding it has been added to this Technical
Specification as well. This colour image encoding provides a way to represent output-referred images
that does not limit the colour gamut to those colours capable of being displayed on a CRT monitor,
such as that represented by the sRGB colour encoding, or require the use of negative RGB colorimetry
coordinates, such as with extended sRGB colour encodings like bg-sRGB.
An extended colour-gamut colour encoding is particularly desirable for professional photography
applications. For example, colours used for company logos may be outside a monitor gamut and would
therefore need to be clipped or compressed to a less saturated colour. Similarly, scanned photographic
prints that are to be duplicated may contain colours outside a monitor RGB colour-gamut. By using a
standard output-referred extended gamut colour image encoding, images containing such colours can
be stored, interchanged, manipulated, and later printed, without limiting or distorting the colours of the
final output.
The European Colour Initiative (ECI) RGB colour image encoding [eciRGB (2008)] specified in this
international standard meets the needs of these types of applications.
The primaries of eciRGB (2008) are between Reference Output Medium Metric RGB (ROMM RGB) and
sRGB, thereby providing a larger gamut than sRGB, together with lower quantization errors than ROMM
RGB. The tone curve has an encoding linear to the L* axis defined in the CIE 1976 (L*, a*, b*) colour space
(CIELAB 1976).
This Technical Specification has been prepared to provide sufficient documentation, consistent with the
definitions of ISO 22028-1, to allow the imaging community adequate opportunity for implementation and
evaluation of this colour image encoding. It is anticipated that, when there is sufficient implementation
of, and practical experience in the use of, eciRGB (2008), this Technical Specification can be revised as
an International Standard.
The European Colour Initiative owns the copyright on the name eciRGB (2008) and has granted ISO the
irrevocable non-exclusive right to use the name for the purpose of this Technical Specification. A colour
encoding named eciRGB was initiated by ECI in 2004. A second version of this encoding with a modified
tonal curve was defined in 2008. Because of its importance to the European photographers and graphic arts
industry, this Technical Specification was prepared in order to fully define eciRGB according to ISO 22028-1.
TECHNICAL SPECIFICATION ISO/TS 22028-4:2012(E)
Photography and graphic technology — Extended colour
encodings for digital image storage, manipulation and
interchange —
Part 4:
European Colour Initiative RGB colour image encoding
[eciRGB (2008)]
1 Scope
This Technical Specification defines an extended colour-gamut output-referred RGB colour image
encoding designated as European Colour Initiative RGB [eciRGB (2008)]. Digital images encoded using
eciRGB (2008) can be manipulated, stored, transmitted, displayed, or printed by digital still picture
imaging systems. Two precision levels are defined, using 8 bits/channel and 16 bits/channel.
2 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 3664:2009, Graphic technology and photography — Viewing conditions
ISO 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
ISO 22028-1, Photography and graphic technology — Extended colour encodings for digital image storage,
manipulation and interchange — Part 1: Architecture and requirements
CIE Publication 15, Colorimetry
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
adapted white
colour stimulus that an observer who is adapted to the viewing environment would judge to be perfectly
achromatic and to have a luminance factor of unity, i.e. absolute colorimetric coordinates that an observer
would consider to be a perfect white diffuser
NOTE The adapted white can vary within a scene.
3.2
additive RGB colour space
a colorimetric colour space having three colour primaries (generally red, green and blue) such that CIE
XYZ tristimulus values can be determined from the RGB colour space values by forming a weighted
combination of the CIE XYZ tristimulus values for the individual colour primaries, where the weights are
proportional to the radiometrically linear colour space values for the corresponding colour primaries
NOTE 1 A simple linear 3 × 3 matrix transformation can be used to transform between CIE XYZ tristimulus
values and the radiometrically linear colour space values for an additive RGB colour space.
NOTE 2 Additive RGB colour spaces are defined by specifying the CIE chromaticity values for a set of additive
RGB primaries and a colour space white point, together with a colour component transfer function
3.3
colorimetric colour space
a colour space having an exact and simple relationship to CIE colorimetric values
NOTE Colorimetric colour spaces include those defined by CIE (e.g. CIE XYZ, CIELAB, CIELUV, etc.), as well as
colour spaces that are simple transformations of those colour spaces (e.g. additive RGB colour spaces).
3.4
colour component transfer function
single variable, monotonic mathematical function applied individually to one or more colour channels
of a colour space
NOTE 1 Colour component transfer functions are frequently used to account for the nonlinear response of a
reference device and/or to improve the visual uniformity of a colour space.
NOTE 2 Generally, colour compone
...
TECHNICAL ISO/TS
SPECIFICATION 22028-4
First edition
2012-11-01
Photography and graphic
technology — Extended colour
encodings for digital image storage,
manipulation and interchange —
Part 4:
European Colour Initiative RGB colour
image encoding [eciRGB (2008)]
Photographie et technologie graphique — Codages par couleurs
étendues pour stockage, manipulation et échange d’image numérique —
Partie 4: Codage d’image en couleurs RGB par initiative de couleur
européenne [eciRGB(2008)]
Reference number
©
ISO 2012
© ISO 2012
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 copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 4
4.1 General . 4
4.2 Reference viewing environment . 5
4.3 Reference display . 6
4.4 eciRGB (2008) colour image encoding . 7
Annex A (informative) The eciRGB (2008) ICC profile considerations .11
Annex B (informative) Practical tolerances for viewing eciRGB (2008) encoded images .12
Annex C (informative) Comparison of primaries.15
Bibliography .17
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.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of document:
— an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical
experts in an ISO working group and is accepted for publication if it is approved by more than 50 %
of the members of the parent committee casting a vote;
— an ISO Technical Specification (ISO/TS) represents an agreement between the members of a
technical committee and is accepted for publication if it is approved by 2/3 of the members of the
committee casting a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for
a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or
ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be
transformed into an International Standard or be withdrawn.
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/TS 22028-4 was prepared by Technical Committee ISO/TC 42, Photography.
ISO/TS 22028 consists of the following parts, under the general title Photography and graphic
technology — Extended colour encodings for digital image storage, manipulation and interchange:
— Part 1: Architecture and requirements
— Part 2: Reference output medium metric RGB colour image encoding (ROMM RGB)
— Part 3: Reference input medium metric RGB colour image encoding (RIMM RGB) [Technical Specification]
— Part 4: European Colour Initiative RGB colour image encoding [eciRGB (2008)] [Technical Specification]
iv © ISO 2012 – All rights reserved
Introduction
This Technical Specification has been developed in order to meet the industry need for a complete,
fully documented, publicly available definition of an output-referred extended gamut RGB colour image
encoding which is optimized for an 8-bit encoding and the conversion of RGB images into offset print
colour spaces. Since users have also asked for a 16-bit encoding it has been added to this Technical
Specification as well. This colour image encoding provides a way to represent output-referred images
that does not limit the colour gamut to those colours capable of being displayed on a CRT monitor,
such as that represented by the sRGB colour encoding, or require the use of negative RGB colorimetry
coordinates, such as with extended sRGB colour encodings like bg-sRGB.
An extended colour-gamut colour encoding is particularly desirable for professional photography
applications. For example, colours used for company logos may be outside a monitor gamut and would
therefore need to be clipped or compressed to a less saturated colour. Similarly, scanned photographic
prints that are to be duplicated may contain colours outside a monitor RGB colour-gamut. By using a
standard output-referred extended gamut colour image encoding, images containing such colours can
be stored, interchanged, manipulated, and later printed, without limiting or distorting the colours of the
final output.
The European Colour Initiative (ECI) RGB colour image encoding [eciRGB (2008)] specified in this
international standard meets the needs of these types of applications.
The primaries of eciRGB (2008) are between Reference Output Medium Metric RGB (ROMM RGB) and
sRGB, thereby providing a larger gamut than sRGB, together with lower quantization errors than ROMM
RGB. The tone curve has an encoding linear to the L* axis defined in the CIE 1976 (L*, a*, b*) colour space
(CIELAB 1976).
This Technical Specification has been prepared to provide sufficient documentation, consistent with the
definitions of ISO 22028-1, to allow the imaging community adequate opportunity for implementation and
evaluation of this colour image encoding. It is anticipated that, when there is sufficient implementation
of, and practical experience in the use of, eciRGB (2008), this Technical Specification can be revised as
an International Standard.
The European Colour Initiative owns the copyright on the name eciRGB (2008) and has granted ISO the
irrevocable non-exclusive right to use the name for the purpose of this Technical Specification. A colour
encoding named eciRGB was initiated by ECI in 2004. A second version of this encoding with a modified
tonal curve was defined in 2008. Because of its importance to the European photographers and graphic arts
industry, this Technical Specification was prepared in order to fully define eciRGB according to ISO 22028-1.
TECHNICAL SPECIFICATION ISO/TS 22028-4:2012(E)
Photography and graphic technology — Extended colour
encodings for digital image storage, manipulation and
interchange —
Part 4:
European Colour Initiative RGB colour image encoding
[eciRGB (2008)]
1 Scope
This Technical Specification defines an extended colour-gamut output-referred RGB colour image
encoding designated as European Colour Initiative RGB [eciRGB (2008)]. Digital images encoded using
eciRGB (2008) can be manipulated, stored, transmitted, displayed, or printed by digital still picture
imaging systems. Two precision levels are defined, using 8 bits/channel and 16 bits/channel.
2 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 3664:2009, Graphic technology and photography — Viewing conditions
ISO 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
ISO 22028-1, Photography and graphic technology — Extended colour encodings for digital image storage,
manipulation and interchange — Part 1: Architecture and requirements
CIE Publication 15, Colorimetry
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
adapted white
colour stimulus that an observer who is adapted to the viewing environment would judge to be perfectly
achromatic and to have a luminance factor of unity, i.e. absolute colorimetric coordinates that an observer
would consider to be a perfect white diffuser
NOTE The adapted white can vary within a scene.
3.2
additive RGB colour space
a colorimetric colour space having three colour primaries (generally red, green and blue) such that CIE
XYZ tristimulus values can be determined from the RGB colour space values by forming a weighted
combination of the CIE XYZ tristimulus values for the individual colour primaries, where the weights are
proportional to the radiometrically linear colour space values for the corresponding colour primaries
NOTE 1 A simple linear 3 × 3 matrix transformation can be used to transform between CIE XYZ tristimulus
values and the radiometrically linear colour space values for an additive RGB colour space.
NOTE 2 Additive RGB colour spaces are defined by specifying the CIE chromaticity values for a set of additive
RGB primaries and a colour space white point, together with a colour component transfer function
3.3
colorimetric colour space
a colour space having an exact and simple relationship to CIE colorimetric values
NOTE Colorimetric colour spaces include those defined by CIE (e.g. CIE XYZ, CIELAB, CIELUV, etc.), as well as
colour spaces that are simple transformations of those colour spaces (e.g. additive RGB colour spaces).
3.4
colour component transfer function
single variable, monotonic mathematical function applied individually to one or more colour channels
of a colour space
NOTE 1 Colour component transfer functions are frequently used to account for the nonlinear response of a
reference device and/or to improve the visual uniformity of a colour space.
NOTE 2 Generally, colour component transfer functions will be nonlinear functions such as a power-law
(i.e. “gamma”) function or a logarithmic function. However, in some cases a linear colour component transfer
function can be used.
3.5
colour encoding
a generic term for a quantized digital encoding of a colour space, encompassing both colour space
encodings and colour image encodings
3.6
colour gamut
solid in a colour space, consisting of all those colours that are either: present in a specific scene, artwork,
photograph, photomechanical, or other reproduction; or capable of being created using a particular
output device and/or medium
3.7
colour image encoding
digital encoding of the colour values for a digital image, including the specification of a colour space
encoding, together with any information necessary to properly interpret the colour values such as the
image state, the intended image viewing environment and the reference medium
NOTE 1 In some cases the intended image viewing environment will be explicitly defined for the colour image
encoding. In other cases, the intended image viewing environment can be specified on an image-by-image basis
using metadata associated with the digital image.
NOTE 2 Some colour image encodings will indicate particular reference medium characteristics, such as a
reflection print with a specified density range. In other cases the reference medium will be not applicable, such as
with a scene-referred colour image encoding, o
...
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