IEC 61966-2-5:2007

Multimedia systems and equipment - Colour measurement and management - Part 2-5: Colour management - Optional RGB colour space - opRGB

is applicable to the encoding and communication of RGB colours optionally used in computer systems and similar applications by defining encoding transformations for use in defined reference conditions.

General Information

• Status: Published
• Publication Date: 06-Nov-2007
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 17.180.20 - Colours and measurement of light
• ICS: 33.160.60 - Multimedia systems and teleconferencing equipment
• Technical Committee: TC 100 - Audio, video and multimedia systems and equipment
• Current Stage: PPUB - Publication issued
• Completion Date: 07-Nov-2007

Standards Content (Sample)

IEC 61966-2-5
Edition 1.0 2007-11
INTERNATIONAL
STANDARD
Multimedia systems and equipment – Colour measurement and management –
Part 2-5: Colour management – Optional RGB colour space – opRGB

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IEC 61966-2-5
Edition 1.0 2007-11
INTERNATIONAL
STANDARD
Multimedia systems and equipment – Colour measurement and management –
Part 2-5: Colour management – Optional RGB colour space – opRGB

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
S
ICS 17.180.20; 33.160.60 ISBN 2-8318-9350-X

– 2 – 61966-2-5 © IEC:2007(E)
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative references .6
3 Terms and definitions .6
4 Reference conditions.8
4.1 Reference image display system characteristics.8
4.2 Reference viewing conditions .8
4.3 Reference observer.9
5 Encoding transformations .9
5.1 Introduction .9
5.2 Transformation from opRGB values to CIE 1931 XYZ values.9
5.3 Transformation from CIE 1931 XYZ values to opRGB values.9

Annex A (normative) Transformation between opRGB values and YCC values for
image compression.11
Annex B (informative) Example transformation between opRGB values and sYCC
values.14
Annex C (informative) Example interpretation for colour image encoding specifications .19

Bibliography.21

Table 1 – CIE chromaticities and CIE standard illuminant .8

61966-2-5 © IEC:2007(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MULTIMEDIA SYSTEMS AND EQUIPMENT –
COLOUR MEASUREMENT AND MANAGEMENT –

Part 2-5: Colour management –
Optional RGB colour space –
opRGB
FOREWORD
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61966-2-5 has been prepared by technical area 2: Colour
measurement and management, of IEC technical committee 100: Audio, video and multimedia
systems and equipment.
The text of this standard is based on the following documents:
CDV Report on voting
100/1212/CDV 100/1282/RVC
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – 61966-2-5 © IEC:2007(E)
The list of all parts of the IEC 61966 series, under the general title Multimedia systems and
equipment – Colour measurement and management, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

61966-2-5 © IEC:2007(E) – 5 –
INTRODUCTION
The colour gamut for various image I/O devices has been gradually extended in recent years.
IEC 61966-2-1 “Multimedia Systems and Equipment – Colour Measurement and
Management – Part 2-1: Colour Management – Default RGB Colour Space – sRGB” is the
International Standard issued in 1999, based on the colour characteristics of contemporary
CRT displays.
Subsequently, displays with a wider colour gamut have been commercialized in order to better
cover the colour gamut that is available for digital still cameras, printers and other devices.
This International Standard specifies a colour image encoding similar to the sRGB encoding,
but based on a wider gamut colour space than sRGB. The rendering of the image for specific
applications is beyond the scope of this standard. A display that has a colour gamut wider
than conventional displays has been selected as the “Reference image display system
characteristics” in this standard. These wider colour gamut displays provide advantages in
commercial printing industry workflows and are intended to be used by professional
photographers, prepress industry including DTP and designers.
.
– 6 – 61966-2-5 © IEC:2007(E)
MULTIMEDIA SYSTEMS AND EQUIPMENT –
COLOUR MEASUREMENT AND MANAGEMENT –

Part 2-5: Colour management –
Optional RGB colour space –
opRGB
1 Scope
This part of IEC 61966 is applicable to the encoding and communication of RGB colours
optionally used in computer systems and similar applications by defining encoding
transformations for use in defined reference conditions.
If actual conditions differ from the reference conditions, additional rendering transformations
may be required. Such additional rendering transformations are beyond the scope of this
standard.
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.
IEC 60050(845):1987, International Electrotechnical Vocabulary (IEV) – Chapter 845:
Lighting / CIE 17.4:1987, International Lighting Vocabulary (Joint IEC/CIE publication)
ISO 3664:2000, Viewing conditions – Graphic technology and photography
ISO/CIE 10527:1991, CIE standard colorimetric observers
CIE 15:2004, Colorimetry, 3rd ed.
CIE 122:1996, The relationship between digital and colorimetric data for computer-controlled
CRT displays
CIE 1931, CIE XYZ color space
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. Definitions of
colour space, illuminance, luminance, tristimulus and other related lighting terms are provided
in IEC 60050(845).
3.1
ambient illuminance level
illuminance level due to lighting in the viewing environment, excluding that from the display,
measured in the plane of the display faceplate

61966-2-5 © IEC:2007(E) – 7 –
3.2
ambient white point
coordinate point in the CIE 1931 XYZ chromaticity coordinate defined by ISO/CIE 10527 and
CIE 15.2 due to lighting in the viewing environment, excluding that from the display, measured
in the plane of the display faceplate
3.3
display illuminant white point
point in the CIE 1931 XYZ chromaticity diagram defined by ISO/CIE 10527 and CIE 15.2, at
which the red, green and blue intensities are at 100 %, measured in a direction perpendicular
to the display faceplate
3.4
display background
environment of the colour element, extending typically for about ten degrees from the edge of
the proximal field in all, or most, directions. When the proximal field is the same colour as the
background, the latter is regarded as extending from the edge of the colour element
considered
3.5
display black level
the luminance level characteristic measured in a direction perpendicular to the display
faceplate, including unwanted leak light through the faceplate and veiling glare from ambient
illumination, at which the red, green and blue intensities are at 0 %
3.6
veiling glare
light, reflected from an imaging medium, that has not been modulated by the means used to
produce the image
NOTE In CIE 122, the veiling glare of a CRT display is referred to as ambient flare.
3.7
display model offset
parameter measured consistently with CIE 122, representing the black offset level of the
display grid voltage
3.8
display input/output characteristic
transfer characteristic relating the normalised digital code value and the normalised output
luminance as represented by a power function
3.9
display luminance level
luminance of the display measured consistently with CIE 122
3.10
display surround
field outside the background, filling the field of vision
3.11
display proximal field
immediate environment of t
...