ISO/TS 22028-3:2012

Photography and graphic technology — Extended colour encodings for digital image storage, manipulation and interchange — Part 3: Reference input medium metric RGB colour image encoding (RIMM RGB)

ISO 22028-3:2012 specifies a family of scene-referred extended colour gamut RGB colour image encodings designated as reference input medium metric RGB (RIMM RGB). Digital images encoded using RIMM RGB can be manipulated, stored, transmitted, displayed or printed by digital still picture imaging systems. Three precision levels are defined using 8-, 12- and 16-bits/channel. An extended luminance dynamic range version of RIMM RGB is also defined, designated as extended reference input medium metric RGB (ERIMM RGB). Two precision levels of ERIMM RGB are defined using 12- and 16-bits/channel. FP-RIMM RGB, a floating point version of RIMM RGB, defines the expression method of RIMM RGB in a floating point figure. Three precision levels of FP-RIMM RGB are defined using 16-, 32- and 64-bits/channel.

Photographie et technologie graphique — Codages par couleurs étendues pour stockage, manipulation et échange d'image numérique — Partie 3: Codage d'image en couleurs RVB par référence d'entrée par voie métrique

Fotografija in grafična tehnologija - Razširjeno barvno kodiranje za shranjevanje, izmenjavo in ravnanje z digitalnimi slikami - 3. del: Referenčna vhodna medijska metrika RGB barvnega kodiranja slik (RIMM RGB)

General Information

• Status: Withdrawn
• Publication Date: 23-Jul-2012
• ICS: 37.040.99 - Other standards related to photography
• ICS: 37.100.01 - Graphic technology in general
• Technical Committee: ISO/TC 42 - Photography
• Drafting Committee: ISO/TC 42/WG 23 - Joint ISO/TC 42 - ISO/TC 130 - CIE WG: Extended colour encodings for digital image storage, manipulation and interchange
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 06-Jan-2023
• Ref Project: SIST-TS ISO/TS 22028-3:2014 - Photography and graphic technology - Extended colour encodings for digital image storage, manipulation and interchange - Part 3: Reference input medium metric RGB colour image encoding (RIMM RGB)

Relations

• Revises: ISO/TS 22028-3:2006 - Photography and graphic technology — Extended colour encodings for digital image storage, manipulation and interchange — Part 3: Reference input medium metric RGB colour image encoding (RIMM RGB)
• Effective Date: 01-Jan-2011
• Revised: ISO 22028-3:2023 - Photography and graphic technology — Extended colour encodings for digital image storage, manipulation and interchange — Part 3: Reference input medium metric RGB colour image encoding (RIMM RGB)
• Effective Date: 06-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TS ISO/TS 22028-3:2014
01-marec-2014
1DGRPHãþD
SIST-TS ISO/TS 22028-3:2011
)RWRJUDILMDLQJUDILþQDWHKQRORJLMD5D]ãLUMHQREDUYQRNRGLUDQMH]DVKUDQMHYDQMH
L]PHQMDYRLQUDYQDQMH]GLJLWDOQLPLVOLNDPLGHO5HIHUHQþQDYKRGQDPHGLMVND
PHWULND5*%EDUYQHJDNRGLUDQMDVOLN5,005*%
Photography and graphic technology - Extended colour encodings for digital image
storage, manipulation and interchange - Part 3: Reference input medium metric RGB
colour image encoding (RIMM RGB)
Photographie et technologie graphique - Codages par couleurs étendues pour stockage,
manipulation et échange d'image numérique - Partie 3: Codage d'image en couleurs
RVB par référence d'entrée par voie métrique
Ta slovenski standard je istoveten z: ISO/TS 22028-3:2012
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
SIST-TS ISO/TS 22028-3:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS ISO/TS 22028-3:2014

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SIST-TS ISO/TS 22028-3:2014
TECHNICAL ISO/TS
SPECIFICATION 22028-3
Second edition
2012-08-01
Photography and graphic
technology — Extended colour
encodings for digital image storage,
manipulation and interchange —
Part 3:
Reference input medium metric RGB
colour image encoding (RIMM RGB)
Photographie et technologie graphique — Codages par couleurs
étendues pour stockage, manipulation et échange d’image numérique —
Partie 3: Codage d’image en couleurs RVB par référence d’entrée par
voie métrique
Reference number
ISO/TS 22028-3:2012(E)
©
ISO 2012

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SIST-TS ISO/TS 22028-3:2014
ISO/TS 22028-3:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© 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 [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved

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SIST-TS ISO/TS 22028-3:2014
ISO/TS 22028-3:2012(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Requirements . 5
4.1 General . 5
4.2 Adopted white . 7
4.3 Reference medium primaries and white point . 7
4.4 RIMM RGB, ERIMM RGB, FP-RIMM RGB colour image encoding . 7
4.5 Inverse RIMM RGB transformation .11
Annex A (informative) Example colour rendering transform from RIMM RGB to ROMM RGB .14
Bibliography .19
© ISO 2012 – All rights reserved iii

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SIST-TS ISO/TS 22028-3:2014
ISO/TS 22028-3:2012(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.
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 22028-3 was prepared by Technical Committee ISO/TC 42, Photography.
This second edition cancels and replaces the first edition (ISO/TS 22028-3:2006), which has been
technically revised.
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]
The following parts are under preparation:
— Part 4: European Colour Initiative RGB colour image encoding [eciRGB (2008)] [Technical Specification]
iv © ISO 2012 – All rights reserved

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SIST-TS ISO/TS 22028-3:2014
ISO/TS 22028-3:2012(E)
Introduction
This part of ISO 22028 has been developed in order to meet the industry need for a complete, fully-
documented, publicly-available definition of a wide-primary scene-referred extended colour gamut
red-green-blue (RGB) colour image encoding. This encoding provides a way to represent scene-referred
images that does not limit the colour gamut to those colours capable of being displayed on a CRT monitor,
or require the use of negative RGB colourimetry coordinates.
A scene-referred extended colour gamut colour encoding is particularly desirable for professional
photography applications. For example, colours captured by digital cameras, as well as conventional
capture devices such as photographic film, can be outside those that can be represented within the
colour gamut of a typical monitor or other types of output devices. Similarly, scene-referred images can
have a larger luminance dynamic range than output-referred images since they have not been modified
by a colour rendering process to fit the images to a specific output medium applying appropriate tone and
colour reproduction aims. Retaining the unrendered scene-referred image data has the advantage that
it preserves the option to make decisions about how a particular image is to be rendered. For example,
a scene-referred image of a backlit scene can retain information about both the dark foreground region
and the bright background region of the scene. This information can be used to make a properly exposed
print of either the foreground region or the background region, or alternatively can be used to create an
improved image by rendering the two regions differently.
By using a standard scene-referred extended colour gamut colour image encoding, images can be stored,
interchanged and manipulated without restricting the image to a particular rendering intent or output
device. The reference input medium metric RGB (RIMM RGB) colour encoding specified in this part of
ISO 22028 meets the needs of these types of applications. An extended dynamic range version of this
colour image encoding known as extended reference input medium metric RGB (ERIMM RGB), and a
floating point version known as FP-RIMM RGB are also specified for use with high-dynamic range input
sources. The scene-referred RIMM RGB colour image encoding is intended to be complementary to the
output-referred ROMM RGB colour image encoding specified in ISO/TS 22028-2. Both colour encodings
are based on the same “wide RGB” additive colour space to facilitate the development of image processing
algorithms and simple colour rendering transformations to convert scene-referred RIMM RGB images to
rendered output-referred ROMM RGB images.
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 patents concerning extended range colour
encodings given in 4.4 and 4.5. ISO takes no position concerning the evidence, validity and scope of this
patent right.
The holder of this patent right has assured 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
Director, Intellectual Property Agreements and Standards
Eastman Kodak Company
343 State StreetRochester
New York 14650-0211, USA
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights other than those identified above. ISO shall not be held responsible for identifying any or
all such patent rights.
© ISO 2012 – All rights reserved v

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SIST-TS ISO/TS 22028-3:2014

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SIST-TS ISO/TS 22028-3:2014
TECHNICAL SPECIFICATION ISO/TS 22028-3:2012(E)
Photography and graphic technology — Extended colour
encodings for digital image storage, manipulation and
interchange —
Part 3:
Reference input medium metric RGB colour image
encoding (RIMM RGB)
1 Scope
This part of ISO 22028 specifies a family of scene-referred extended colour gamut RGB colour image
encodings designated as reference input medium metric RGB (RIMM RGB). Digital images encoded using
RIMM RGB can be manipulated, stored, transmitted, displayed or printed by digital still picture imaging
systems. Three precision levels are defined using 8-, 12- and 16-bits/channel.
An extended luminance dynamic range version of RIMM RGB is also defined, designated as extended
reference input medium metric RGB (ERIMM RGB). Two precision levels of ERIMM RGB are defined
using 12- and 16-bits/channel.
FP-RIMM RGB, a floating point version of RIMM RGB, defines the expression method of RIMM RGB
in a floating point figure. Three precision levels of FP-RIMM RGB are defined using 16-, 32- and
64-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 12234-2, Electronic still-picture imaging — Removable memory — Part 2: TIFF/EP image data format
ISO 22028-1:2004, Photography and graphic technology — Extended colour encodings for digital image
storage, manipulation and interchange — Part 1:Architecture and requirements
1)
ISO 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
CIE Publication 15, Colorimetery
IEEE 754, IEEE Standard for Floating-Point Arithmetic
1) Replaces ISO/CIE 10527.
© ISO 2012 – All rights reserved 1

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SIST-TS ISO/TS 22028-3:2014
ISO/TS 22028-3:2012(E)
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 colourimetric 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
colourimetric 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
adopted white
spectral radiance distribution as seen by an image capture or measurement device and converted to
colour signals that are considered to be perfectly achromatic and to have an observer adaptive luminance
factor of unity; i.e. colour signals that are considered to correspond to a perfect white diffuser
NOTE 1 The adopted white can vary within a scene, if such variation is supported by the imaging system.
NOTE 2 The adopted white is not required to be an estimate or approximation of the adapted white. For
example, if a scene lit by tungsten illumination is captured using a DSC with the white balance set to D55 (daylight),
the adopted white will be D55 but the adapted white will be closer to a tungsten illuminant (e.g. ISO 7589 Studio
Tungsten or CIE Illuminant A).
NOTE 3 See 3.1.
3.4
colourimetric colour space
colour space having an exact and simple relationship to CIE colourimetric values
NOTE Colourimetric colour spaces include those defined by CIE (e.g. CIE XYZ, CIELAB, CIELUV), as well as
colour spaces that are simple transformations of those colour spaces (e.g. additive RGB colour spaces).
3.5
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.
3.6
colour encoding
generic term for a quantized digital encoding of a colour space, encompassing both colour space
encodings and colour image encodings
2 © ISO 2012 – All rights reserved

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SIST-TS ISO/TS 22028-3:2014
ISO/TS 22028-3:2012(E)
3.7
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
3.8
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 not be applicable, such
as with a scene-referred colour image encoding, or will be specified using image metadata.
NOTE 3 Colour image encodings are not limited to pictorial digital images that originate from an original
scene, but are also applicable to digital images with content such as text, line art, vector graphics and other forms
of original artwork.
3.9
colour rendering
mapping of image data representing the colour-space coordinates of the elements of a scene to output-
referred image data representing the colour space coordinates of the elements of a reproduction
NOTE Colour rendering generally consists of one or more of the following:
— compensating for differences in the input and output viewing conditions;
— tone scale and gamut mapping to map the scene colours onto the dynamic range and colour gamut
of the reproduction;
— applying preference adjustments.
3.10
colour space
geometric representation of colours in space, usually of three dimensions
[CIE Publication 17.4:1987, 845-03-25]
3.11
colour space encoding
digital encoding of a colour space, including the specification of a digital encoding method, and a colour
space value range
NOTE Multiple colour space encodings can be defined based on a single colour space where the different
colour space encodings have different digital encoding methods and/or colour space value ranges. (For example,
8-bit sRGB and 10-bit e-sRGB are different colour space encodings based on a particular RGB colour space.)
3.12
colour space white point
colour stimulus to which colour space values are normalized
NOTE It is not necessary that the colour space white point correspond to the assumed adapted white point
and/or the reference medium white point for a colour image encoding.
© ISO 2012 – All rights reserved 3

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SIST-TS ISO/TS 22028-3:2014
ISO/TS 22028-3:2012(E)
3.13
image state
attribute of a colour image encoding indicating the rendering state of the image data
NOTE The primary image states defined in this document are the scene-referred image state, the original-
referred image state and the output-referred image state.
3.14
luminance factor
ratio of the luminance of the surface element in the given direction to that of a perfect reflecting or
transmitting diffuser identically illuminated
[CIE Publication 17.4:1987, 845-04-69]
3.15
observer adaptive luminance factor
ratio of the luminance of a stimulus to the luminance of a stimulus that an observer adapted to the
viewing environment would interpret to be a perfect white diffuser
3.16
output-referred image state
image state associated with image data that represents the colour space coordinates of the elements of
an image that has undergone colour rendering appropriate for a specified real or virtual output device
and viewing conditions
NOTE 1 When the phrase “output-referred” is used as a qualifier to an object, it implies that the object
is in an output-referred image state. For example, output-referred image data are image data in an output-
referred image state.
NOTE 2 Output referred image data are referred to the specified output device and viewing conditions. A
single scene can be colour rendered to a variety of output-referred representations depending on the anticipated
output viewing conditions, media limitations and/or artistic intents.
NOTE 3 Output-referred image data can become the starting point for a subsequent reproduction process. For
example, sRGB output-referred image data are frequently considered to be the starting point for the colour re-
rendering performed by a printer designed to receive sRGB image data.
3.17
scene
spectral radiances of a view of the natural world as measured from a specified vantage point in space
and at a specified time
NOTE A scene can correspond to an actual view of the natural world or to a computer-generated virtual
scene simulating such a view.
3.18
scene-referred image state
image state associated with image data that represents estimates of the colour space coordinates of the
elements of a scene
NOTE 1 When the phrase “scene-referred” is used as a qualifier to an object, it implies that the object is in a
scene-referred image state. For example, scene-referred image data are image data in a scene-referred image state.
NOTE 2 Scene-referred image data can be determined from raw DSC image data before colour rendering is
performed. Generally, DSCs do not write scene-referred image data in image files, but some do so in a special mode
intended for this purpose. Typically, DSCs write standard output-referred image data where colour rendering has
already been performed.
NOTE 3 Scene-referred image data typically represents relative scene colourimetry estimates. Absolute scene
colourimetry estimates can be calculated using a scaling factor. The scaling factor can be derived from additional
information such as the image OECF, FNumber or ApertureValue, and ExposureTime or ShutterSpeedValue tags.
4 © ISO 2012 – All rights reserved

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SIST-TS ISO/TS 22028-3:2014
ISO/TS 22028-3:2012(E)
NOTE 4 Scene-referred image data can contain inaccuracies due to the dynamic range limitations of the capture
device, noise from various sources, quantization, optical blurring and flare that are not corrected for, and colour
analysis errors due to capture device metamerism. In some cases, these sources of inaccuracy can be significant.
NOTE 5 The transformation from raw DSC image data to scene-referred image data depends on the relative
adopted whites selected for the scene and the colour space used to encode the image data. If the chosen scene
adopted white is inappropriate, additional errors will be introduced into the scene-referred image data. These
errors can be correctable if the transformation used to produce the scene-referred image data are known, and the
colour encoding used for the incorrect scene-referred image data has adequate precision and dynamic range.
NOTE 6 The scene can correspond to an actual view of the natural world, or be a computer-generated virtual
scene simulating such a view. It can also correspond to a modified scene determined by applying modifications to
an original scene to produce some different desired scene. Any such scene modifications need to leave the image
in a scene-referred image state and need to be done in the context of an expected colour rendering transform.
3.19
tristimulus value
amounts of the three reference colour stimuli, in a given trichromatic system, required to match the
colour of the stimulus considered
[CIE Publication 17.4:1987, 845-03-22]
3.20
veiling glare
light, reflected from an imaging medium, that has not been modulated by the means used to produce
the image
NOTE 1 Veiling glare lightens and reduces the contrast of the darker parts of an image.
NOTE 2 In CIE Publication 122, the veiling glare of a CRT display is referred to as ambient flare.
3.21
viewing flare
veiling glare that is observed in a viewing environment but not accounted for in radiometric measurements
made using a prescribed measurement geometry
NOTE The viewing flare is expressed as a percentage of the luminance of adapted white.
3.22
working colour space
colour space encoding in which operations such as image edits, enhancements, or colour rendering
are performed
NOTE 1 The image state in a working colour space can change as operations are performed.
NOTE 2 If operations performed in a working colour space are guided by viewing the image on a medium, that
medium and the associated viewing conditions become the reference for the resulting image.
4 Requirements
4.1 General
Reference input medium metric RGB (RIMM RGB) and the ERIMM and FP-RIMM associated versions of
RIMM RGB are extended colour gamut RGB colour image encodings of the colourimetry of a scene-referred
image, white balanced to be relative to a specified adopted white. The image colourimetry is encoded
in terms of an additive RGB colour space associated with a hypothetical additive colour device having a
specified set of primaries and no cross-talk between the colour channels. The RIMM RGB colour image
encoding has a maximum luminance value corresponding to 200 % of a perfect diffuse reflector (i.e. an
observer adaptive luminance factor of 2,0). Extended reference input medium metric RGB (ERIMM RGB)
is an extended luminance dynamic range version of RIMM RGB having a maximum observer adaptive
luminance factor of about 316. The maximum luminance value of FP-RIMM RGB colour image encoding is
© ISO 2012 – All rights reserved 5

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SIST-TS ISO/TS 22028-3:2014
ISO/TS 22028-3:2012(E)
limited only by the floating point encoding range. In RIMM RGB, ERIMM RGB and FP-RIMM RGB, the image
colourimetry shall be based on flareless (or flare corrected) colourimetric measurements as described
in CIE Publication No. 15 using the CIE 1931 standard colourimetric observer defined in ISO 11664-1.
Scene-referred image data may correspond to an actual view of the natural world, or a simulation of
such a view. It may also correspond to a modified scene determined by applying modifications to an
original scene. In order to be appropriate for encoding as RIMM RGB, ERIMM RGB or FP-RIMM RGB, any
scene modifications shall leave the image in a scene-referred image state.
Scene-referred image data may have an associated pre-determined colour rendering transform. When
an associated pre-determined colour rendering transform is present with scene-referred image data,
such an intended colour rendering transform should be included in any image preview path that is used
to provide subjective feedback to a user, unless:
— The user has selected direct viewing of the scene-referred image and intends that modifications are
to be previewed in the scene-referred state.
— The scene-referred image data has been converted to an appropriate working colour space for
manual editing and colour rendering. In this case the user may exercise the option to apply or not
apply an associated pre-determined colour rendering transform, if present, when the scene-referred
image data are converted to the working colour space.
EXAMPLES Scene modifications could include removing haze from the captured image, or allowing a user
to manually adjust the exposure/white balance. It could also include more complex operations such as using a
“dodge-and-burn” algorithm to correct over-exposed regions of a backlit scene. (This can be viewed as being
analogous to “re-lighting” the scene.) Scene modifications could also include applying desired changes to the
scene such as simulating a “night” scene, making grass greener to make it look healthier, or making the sky bluer
to make it look clearer. However, typical colour rendering transforms will include a boost in the midtone contrast
and chroma of the image. Consequently, any boost in colourfulness of the scene (e.g. making the grass greener)
needs to be done with the knowledge that there may be an additional chroma boost during colour rendering.
NOTE 1 The image colourimetry of the scene-referred image can contain ina
...

TECHNICAL ISO/TS
SPECIFICATION 22028-3
Second edition
2012-08-01
Photography and graphic
technology — Extended colour
encodings for digital image storage,
manipulation and interchange —
Part 3:
Reference input medium metric RGB
colour image encoding (RIMM RGB)
Photographie et technologie graphique — Codages par couleurs
étendues pour stockage, manipulation et échange d’image numérique —
Partie 3: Codage d’image en couleurs RVB par référence d’entrée par
voie métrique
Reference number
ISO/TS 22028-3:2012(E)
©
ISO 2012

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ISO/TS 22028-3:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© 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 [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/TS 22028-3:2012(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Requirements . 5
4.1 General . 5
4.2 Adopted white . 7
4.3 Reference medium primaries and white point . 7
4.4 RIMM RGB, ERIMM RGB, FP-RIMM RGB colour image encoding . 7
4.5 Inverse RIMM RGB transformation .11
Annex A (informative) Example colour rendering transform from RIMM RGB to ROMM RGB .14
Bibliography .19
© ISO 2012 – All rights reserved iii

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ISO/TS 22028-3:2012(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.
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 22028-3 was prepared by Technical Committee ISO/TC 42, Photography.
This second edition cancels and replaces the first edition (ISO/TS 22028-3:2006), which has been
technically revised.
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]
The following parts are under preparation:
— Part 4: European Colour Initiative RGB colour image encoding [eciRGB (2008)] [Technical Specification]
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ISO/TS 22028-3:2012(E)
Introduction
This part of ISO 22028 has been developed in order to meet the industry need for a complete, fully-
documented, publicly-available definition of a wide-primary scene-referred extended colour gamut
red-green-blue (RGB) colour image encoding. This encoding provides a way to represent scene-referred
images that does not limit the colour gamut to those colours capable of being displayed on a CRT monitor,
or require the use of negative RGB colourimetry coordinates.
A scene-referred extended colour gamut colour encoding is particularly desirable for professional
photography applications. For example, colours captured by digital cameras, as well as conventional
capture devices such as photographic film, can be outside those that can be represented within the
colour gamut of a typical monitor or other types of output devices. Similarly, scene-referred images can
have a larger luminance dynamic range than output-referred images since they have not been modified
by a colour rendering process to fit the images to a specific output medium applying appropriate tone and
colour reproduction aims. Retaining the unrendered scene-referred image data has the advantage that
it preserves the option to make decisions about how a particular image is to be rendered. For example,
a scene-referred image of a backlit scene can retain information about both the dark foreground region
and the bright background region of the scene. This information can be used to make a properly exposed
print of either the foreground region or the background region, or alternatively can be used to create an
improved image by rendering the two regions differently.
By using a standard scene-referred extended colour gamut colour image encoding, images can be stored,
interchanged and manipulated without restricting the image to a particular rendering intent or output
device. The reference input medium metric RGB (RIMM RGB) colour encoding specified in this part of
ISO 22028 meets the needs of these types of applications. An extended dynamic range version of this
colour image encoding known as extended reference input medium metric RGB (ERIMM RGB), and a
floating point version known as FP-RIMM RGB are also specified for use with high-dynamic range input
sources. The scene-referred RIMM RGB colour image encoding is intended to be complementary to the
output-referred ROMM RGB colour image encoding specified in ISO/TS 22028-2. Both colour encodings
are based on the same “wide RGB” additive colour space to facilitate the development of image processing
algorithms and simple colour rendering transformations to convert scene-referred RIMM RGB images to
rendered output-referred ROMM RGB images.
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 patents concerning extended range colour
encodings given in 4.4 and 4.5. ISO takes no position concerning the evidence, validity and scope of this
patent right.
The holder of this patent right has assured 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
Director, Intellectual Property Agreements and Standards
Eastman Kodak Company
343 State StreetRochester
New York 14650-0211, USA
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights other than those identified above. ISO shall not be held responsible for identifying any or
all such patent rights.
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TECHNICAL SPECIFICATION ISO/TS 22028-3:2012(E)
Photography and graphic technology — Extended colour
encodings for digital image storage, manipulation and
interchange —
Part 3:
Reference input medium metric RGB colour image
encoding (RIMM RGB)
1 Scope
This part of ISO 22028 specifies a family of scene-referred extended colour gamut RGB colour image
encodings designated as reference input medium metric RGB (RIMM RGB). Digital images encoded using
RIMM RGB can be manipulated, stored, transmitted, displayed or printed by digital still picture imaging
systems. Three precision levels are defined using 8-, 12- and 16-bits/channel.
An extended luminance dynamic range version of RIMM RGB is also defined, designated as extended
reference input medium metric RGB (ERIMM RGB). Two precision levels of ERIMM RGB are defined
using 12- and 16-bits/channel.
FP-RIMM RGB, a floating point version of RIMM RGB, defines the expression method of RIMM RGB
in a floating point figure. Three precision levels of FP-RIMM RGB are defined using 16-, 32- and
64-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 12234-2, Electronic still-picture imaging — Removable memory — Part 2: TIFF/EP image data format
ISO 22028-1:2004, Photography and graphic technology — Extended colour encodings for digital image
storage, manipulation and interchange — Part 1:Architecture and requirements
1)
ISO 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
CIE Publication 15, Colorimetery
IEEE 754, IEEE Standard for Floating-Point Arithmetic
1) Replaces ISO/CIE 10527.
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ISO/TS 22028-3:2012(E)
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 colourimetric 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
colourimetric 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
adopted white
spectral radiance distribution as seen by an image capture or measurement device and converted to
colour signals that are considered to be perfectly achromatic and to have an observer adaptive luminance
factor of unity; i.e. colour signals that are considered to correspond to a perfect white diffuser
NOTE 1 The adopted white can vary within a scene, if such variation is supported by the imaging system.
NOTE 2 The adopted white is not required to be an estimate or approximation of the adapted white. For
example, if a scene lit by tungsten illumination is captured using a DSC with the white balance set to D55 (daylight),
the adopted white will be D55 but the adapted white will be closer to a tungsten illuminant (e.g. ISO 7589 Studio
Tungsten or CIE Illuminant A).
NOTE 3 See 3.1.
3.4
colourimetric colour space
colour space having an exact and simple relationship to CIE colourimetric values
NOTE Colourimetric colour spaces include those defined by CIE (e.g. CIE XYZ, CIELAB, CIELUV), as well as
colour spaces that are simple transformations of those colour spaces (e.g. additive RGB colour spaces).
3.5
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.
3.6
colour encoding
generic term for a quantized digital encoding of a colour space, encompassing both colour space
encodings and colour image encodings
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ISO/TS 22028-3:2012(E)
3.7
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
3.8
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 not be applicable, such
as with a scene-referred colour image encoding, or will be specified using image metadata.
NOTE 3 Colour image encodings are not limited to pictorial digital images that originate from an original
scene, but are also applicable to digital images with content such as text, line art, vector graphics and other forms
of original artwork.
3.9
colour rendering
mapping of image data representing the colour-space coordinates of the elements of a scene to output-
referred image data representing the colour space coordinates of the elements of a reproduction
NOTE Colour rendering generally consists of one or more of the following:
— compensating for differences in the input and output viewing conditions;
— tone scale and gamut mapping to map the scene colours onto the dynamic range and colour gamut
of the reproduction;
— applying preference adjustments.
3.10
colour space
geometric representation of colours in space, usually of three dimensions
[CIE Publication 17.4:1987, 845-03-25]
3.11
colour space encoding
digital encoding of a colour space, including the specification of a digital encoding method, and a colour
space value range
NOTE Multiple colour space encodings can be defined based on a single colour space where the different
colour space encodings have different digital encoding methods and/or colour space value ranges. (For example,
8-bit sRGB and 10-bit e-sRGB are different colour space encodings based on a particular RGB colour space.)
3.12
colour space white point
colour stimulus to which colour space values are normalized
NOTE It is not necessary that the colour space white point correspond to the assumed adapted white point
and/or the reference medium white point for a colour image encoding.
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ISO/TS 22028-3:2012(E)
3.13
image state
attribute of a colour image encoding indicating the rendering state of the image data
NOTE The primary image states defined in this document are the scene-referred image state, the original-
referred image state and the output-referred image state.
3.14
luminance factor
ratio of the luminance of the surface element in the given direction to that of a perfect reflecting or
transmitting diffuser identically illuminated
[CIE Publication 17.4:1987, 845-04-69]
3.15
observer adaptive luminance factor
ratio of the luminance of a stimulus to the luminance of a stimulus that an observer adapted to the
viewing environment would interpret to be a perfect white diffuser
3.16
output-referred image state
image state associated with image data that represents the colour space coordinates of the elements of
an image that has undergone colour rendering appropriate for a specified real or virtual output device
and viewing conditions
NOTE 1 When the phrase “output-referred” is used as a qualifier to an object, it implies that the object
is in an output-referred image state. For example, output-referred image data are image data in an output-
referred image state.
NOTE 2 Output referred image data are referred to the specified output device and viewing conditions. A
single scene can be colour rendered to a variety of output-referred representations depending on the anticipated
output viewing conditions, media limitations and/or artistic intents.
NOTE 3 Output-referred image data can become the starting point for a subsequent reproduction process. For
example, sRGB output-referred image data are frequently considered to be the starting point for the colour re-
rendering performed by a printer designed to receive sRGB image data.
3.17
scene
spectral radiances of a view of the natural world as measured from a specified vantage point in space
and at a specified time
NOTE A scene can correspond to an actual view of the natural world or to a computer-generated virtual
scene simulating such a view.
3.18
scene-referred image state
image state associated with image data that represents estimates of the colour space coordinates of the
elements of a scene
NOTE 1 When the phrase “scene-referred” is used as a qualifier to an object, it implies that the object is in a
scene-referred image state. For example, scene-referred image data are image data in a scene-referred image state.
NOTE 2 Scene-referred image data can be determined from raw DSC image data before colour rendering is
performed. Generally, DSCs do not write scene-referred image data in image files, but some do so in a special mode
intended for this purpose. Typically, DSCs write standard output-referred image data where colour rendering has
already been performed.
NOTE 3 Scene-referred image data typically represents relative scene colourimetry estimates. Absolute scene
colourimetry estimates can be calculated using a scaling factor. The scaling factor can be derived from additional
information such as the image OECF, FNumber or ApertureValue, and ExposureTime or ShutterSpeedValue tags.
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ISO/TS 22028-3:2012(E)
NOTE 4 Scene-referred image data can contain inaccuracies due to the dynamic range limitations of the capture
device, noise from various sources, quantization, optical blurring and flare that are not corrected for, and colour
analysis errors due to capture device metamerism. In some cases, these sources of inaccuracy can be significant.
NOTE 5 The transformation from raw DSC image data to scene-referred image data depends on the relative
adopted whites selected for the scene and the colour space used to encode the image data. If the chosen scene
adopted white is inappropriate, additional errors will be introduced into the scene-referred image data. These
errors can be correctable if the transformation used to produce the scene-referred image data are known, and the
colour encoding used for the incorrect scene-referred image data has adequate precision and dynamic range.
NOTE 6 The scene can correspond to an actual view of the natural world, or be a computer-generated virtual
scene simulating such a view. It can also correspond to a modified scene determined by applying modifications to
an original scene to produce some different desired scene. Any such scene modifications need to leave the image
in a scene-referred image state and need to be done in the context of an expected colour rendering transform.
3.19
tristimulus value
amounts of the three reference colour stimuli, in a given trichromatic system, required to match the
colour of the stimulus considered
[CIE Publication 17.4:1987, 845-03-22]
3.20
veiling glare
light, reflected from an imaging medium, that has not been modulated by the means used to produce
the image
NOTE 1 Veiling glare lightens and reduces the contrast of the darker parts of an image.
NOTE 2 In CIE Publication 122, the veiling glare of a CRT display is referred to as ambient flare.
3.21
viewing flare
veiling glare that is observed in a viewing environment but not accounted for in radiometric measurements
made using a prescribed measurement geometry
NOTE The viewing flare is expressed as a percentage of the luminance of adapted white.
3.22
working colour space
colour space encoding in which operations such as image edits, enhancements, or colour rendering
are performed
NOTE 1 The image state in a working colour space can change as operations are performed.
NOTE 2 If operations performed in a working colour space are guided by viewing the image on a medium, that
medium and the associated viewing conditions become the reference for the resulting image.
4 Requirements
4.1 General
Reference input medium metric RGB (RIMM RGB) and the ERIMM and FP-RIMM associated versions of
RIMM RGB are extended colour gamut RGB colour image encodings of the colourimetry of a scene-referred
image, white balanced to be relative to a specified adopted white. The image colourimetry is encoded
in terms of an additive RGB colour space associated with a hypothetical additive colour device having a
specified set of primaries and no cross-talk between the colour channels. The RIMM RGB colour image
encoding has a maximum luminance value corresponding to 200 % of a perfect diffuse reflector (i.e. an
observer adaptive luminance factor of 2,0). Extended reference input medium metric RGB (ERIMM RGB)
is an extended luminance dynamic range version of RIMM RGB having a maximum observer adaptive
luminance factor of about 316. The maximum luminance value of FP-RIMM RGB colour image encoding is
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ISO/TS 22028-3:2012(E)
limited only by the floating point encoding range. In RIMM RGB, ERIMM RGB and FP-RIMM RGB, the image
colourimetry shall be based on flareless (or flare corrected) colourimetric measurements as described
in CIE Publication No. 15 using the CIE 1931 standard colourimetric observer defined in ISO 11664-1.
Scene-referred image data may correspond to an actual view of the natural world, or a simulation of
such a view. It may also correspond to a modified scene determined by applying modifications to an
original scene. In order to be appropriate for encoding as RIMM RGB, ERIMM RGB or FP-RIMM RGB, any
scene modifications shall leave the image in a scene-referred image state.
Scene-referred image data may have an associated pre-determined colour rendering transform. When
an associated pre-determined colour rendering transform is present with scene-referred image data,
such an intended colour rendering transform should be included in any image preview path that is used
to provide subjective feedback to a user, unless:
— The user has selected direct viewing of the scene-referred image and intends that modifications are
to be previewed in the scene-referred state.
— The scene-referred image data has been converted to an appropriate working colour space for
manual editing and colour rendering. In this case the user may exercise the option to apply or not
apply an associated pre-determined colour rendering transform, if present, when the scene-referred
image data are converted to the working colour space.
EXAMPLES Scene modifications could include removing haze from the captured image, or allowing a user
to manually adjust the exposure/white balance. It could also include more complex operations such as using a
“dodge-and-burn” algorithm to correct over-exposed regions of a backlit scene. (This can be viewed as being
analogous to “re-lighting” the scene.) Scene modifications could also include applying desired changes to the
scene such as simulating a “night” scene, making grass greener to make it look healthier, or making the sky bluer
to make it look clearer. However, typical colour rendering transforms will include a boost in the midtone contrast
and chroma of the image. Consequently, any boost in colourfulness of the scene (e.g. making the grass greener)
needs to be done with the knowledge that there may be an additional chroma boost during colour rendering.
NOTE 1 The image colourimetry of the scene-referred image can contain inaccuracies due to the dynamic
range limitations of the capture device, noise from various sources, quantization, optical blurring and flare that
are not corrected for, and colour analysis errors due to capture device metamerism. In some cases, these sources
of inaccuracy can be significant.
Three different precision levels are defined for RIMM RGB, and shall be identified as RIMM8 RGB,
RIMM12 RGB and RIMM16 RGB, for 8-, 12- and 16-bits/channel (24-, 36- and 48-bits/pixel)
representations, respectively.
For extended reference input medium metric RGB (ERIMM RGB), two different precision levels are
defined and shall be identified as ERIMM12 RGB and ERIMM16 RGB, for 12- and 16-bits/channel (36-
and 48-bits/pixel) representations, respectively.
Floating point reference input medium metric RGB (FP-RIMM RGB) is a floating point encoded version of
RIMM RGB with a linear colour component transfer function. Half-, single- or double-precision floating
point numbers, as defined in IEEE 754:2008, may be used in TIFF/EP files as defined in ISO 12234-2,
requiring 48-, 96- and 192-bits/pixel, respectively.
NOTE 2 RIMM RGB, ERIMM RGB or FP-RIMM RGB images are intended for use in system environments that
support scene-referred images. However, they can be interchanged in environments that do not support scene-
referred images if a default colour rendering transform or a full resolution standard output-referred image that
is supported in the environment is associated with the scene-referred image. The TIFF/EP and JPEG 2000 file
formats can use ICC profiles to support RIMM RGB, ERIMM RGB or FP-RIMM RGB images in system environments
designed to support output-referred i
...