ISO 12640-5:2013

INTERNATIONAL ISO
STANDARD 12640-5
First edition
2013-12-15
Graphic technology — Prepress digital
data exchange —
Part 5:
Scene-referred standard colour image
data (RIMM/SCID)
Technologie graphique —Échange de données numériques de
préimpression —
Partie 5: Données d'image standard en couleurs montrées en référence
par scène (RIMM/SCID)
Reference number
©
ISO 2013
This DVD contains:
1) the publication ISO 12640-5:2013 in portable document format (PDF), which can be viewed using
Adobe® Acrobat® Reader;
2) image files NP01RGB.tif to NP27RGB.tif and NS01RGB.tif to NS17RGB.tif, which correspond to the
natural images described in Tables 1 and 2 and depicted in Figure 2;
3) image files S1RGB.tif to S3RGB.tif, which correspond to the synthetic images described in Table 3
and depicted in Figure 3.
Adobe and Acrobat are trademarks of Adobe Systems Incorporated.
©  ISO 2013
All rights reserved. Unless required for installation or otherwise specified, no part of this DVD may be reproduced, stored in a retrieval
system or transmitted in any form or by any means without prior permission from ISO. Requests for permission to reproduce this product
should be addressed to
ISO copyright office  Case postale 56  CH-1211 Geneva 20  Switzerland
Internet copyright@iso.org
Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.
Published in Switzerland
ii © ISO 2013 – All rights reserved

Installation
If this
...

INTERNATIONAL ISO
STANDARD 12640-5
First edition
2013-12-15
Graphic technology — Prepress digital
data exchange —
Part 5:
Scene-referred standard colour image
data (RIMM/SCID)
Technologie graphique —Échange de données numériques de
préimpression —
Partie 5: Données d'image standard en couleurs montrées en référence
par scène (RIMM/SCID)
Reference number
©
ISO 2013
This DVD contains:
1) the publication ISO 12640-5:2013 in portable document format (PDF), which can be viewed using
Adobe® Acrobat® Reader;
2) image files NP01RGB.tif to NP27RGB.tif and NS01RGB.tif to NS17RGB.tif, which correspond to the
natural images described in Tables 1 and 2 and depicted in Figure 2;
3) image files S1RGB.tif to S3RGB.tif, which correspond to the synthetic images described in Table 3
and depicted in Figure 3.
Adobe and Acrobat are trademarks of Adobe Systems Incorporated.
©  ISO 2013
All rights reserved. Unless required for installation or otherwise specified, no part of this DVD may be reproduced, stored in a retrieval
system or transmitted in any form or by any means without prior permission from ISO. Requests for permission to reproduce this product
should be addressed to
ISO copyright office  Case postale 56  CH-1211 Geneva 20  Switzerland
Internet copyright@iso.org
Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.
Published in Switzerland
ii © ISO 2013 – All rights reserved

Installation
If this
...

INTERNATIONAL ISO
STANDARD 12640-5
First edition
2013-12-15
Graphic technology — Prepress digital
data exchange —
Part 5:
Scene-referred standard colour image
data (RIMM/SCID)
Technologie graphique — Échange de données numériques de
préimpression —
Partie 5: Données d’image standard en couleurs montrées en
référence par scène (RIMM/SCID)
Reference number
©
ISO 2013
© ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested 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 2013 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Data description . 4
4.1 General . 4
4.2 Data set definition . 4
4.3 Image data arrangement . 4
4.4 Data colour encoding . 4
4.5 Natural images . 5
4.6 Synthetic images .19
5 Electronic data .23
Annex A (normative) Guidance for use of digital data .25
Annex B (normative) Check-sum data .27
Annex C (informative) Typical TIFF/IT file header used for image files .29
Annex D (informative) Label text insertion .31
Annex E (informative) Histogram and colour gamut .33
Bibliography .49
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is Technical Committee ISO/TC 130, Graphic technology.
ISO 12640 consists of the following parts, under the general title Graphic technology — Prepress digital
data exchange:
— Part 1: CMYK standard colour image data (CMYK/SCID)
— Part 2: XYZ/sRGB standard colour image data (XYZ/SCID)
— Part 3: CIELAB standard colour image data (CIELAB/SCID)
— Part 4: Wide gamut display-referred standard colour image data (Adobe RGB(1998)/SCID)
— Part 5: Scene-referred standard colour image data (RIMM/SCID)
iv © ISO 2013 – All rights reserved

Introduction
0.1 Need for standard colour image data
Standard colour image data provide a set of data that can be used for any of the following tasks:
— evaluating the colour reproduction of imaging systems;
— evaluating colour image output devices;
— evaluating the effect of image processing algorithms applied to the images;
— evaluating the coding technologies necessary for the storage and transmission of high-definition
image data, etc.
These standard, well-defined image data sets, are typical of the high quality image content commonly
encountered when capturing and printing images. Users can therefore be confident that the images
should produce good quality reproductions if properly rendered, and that they provide a reasonable
test of the evaluation task being undertaken. No limited set of images can fully test any system, but the
sets provided give as reasonable a test as can be expected from a limited image set. Furthermore, the
existence of a standard set enables users in different locations to produce comparisons without the need
to exchange images prior to reproduction.
Different applications require that the standard image data be provided in different image states
using different image encodings (see ISO 22028-1), so the user needs to select those appropriate to
the evaluation task being undertaken. While transformation of the image data to another image state
is always possible, there is, in general, no agreement amongst experts as to how this should be done.
Thus, it has been considered preferable to provide data in different image states in the various parts of
ISO 12640. The relationship between image states is shown in Figure 1 along with the applicable parts
of ISO 12640.
Figure 1 — Relationship between image states
ISO 12640-1 provides a set of 8 bits/channel data that is defined in terms of CMYK dot percentages.
The colours resulting from reproduction of CMYK data are strictly defined only at the time of printing,
and as such the data are only applicable to evaluation of CMYK printing applications. Transformations
to other image states and colour encodings might not be well defined. In fact, the data might not even
be useful for CMYK printing processes different from those typically found in traditional graphic arts
applications, as the image data are defined to produce “pleasing” images when reproduced on systems
using “typical” inks and producing “typical” tone value rendering. Printing systems that use inks of a
distinctly different colour, or produce a very different tone value rendering, will not reproduce them
as pleasing images without a well-defined colour transformation. Moreover, with a bit depth of only 8
bits/channel, any colour transformation employed might well introduce artefacts.
ISO 12640-2 provides a set of test image data encoded both as XYZ values with each channel scaled to the
range 0-65535, and as sRGB (defined in IEC 61966-2-1), with a bit depth of 8 bits/channel. (The higher bit
depth for the XYZ encoding is necessary because of the perceptual non-uniformity of the linear colour
space.) Both sets of data are optimized for viewing on a reference sRGB display in the reference sRGB
viewing environment, and relative to CIE standard illuminant D65 for which the XYZ tristimulus values
were computed prior to scaling. The images are mainly designed to be used on systems utilizing sRGB
as the reference encoding, and as such are primarily applicable to systems for which a colour monitor
similar to the sRGB reference display is the “hub” device. Although such systems are used for consumer
photography, they are less popular in the graphic arts industry because the sRGB colour gamut is quite
different in shape from the colour gamut of typical offset printing. This difference can necessitate fairly
aggressive colour re-rendering to produce optimal prints from sRGB image data.
ISO 12640-3 provides a set of test image data with a large reflection medium colour gamut, illuminated
using illuminant D50. The bit depth of the natural images is 16 bits/channel, while the colour charts and
vi © ISO 2013 – All rights reserved

vignettes are 8 bits/channel. In order to be useful for applications where large, print-referred output
gamuts are encountered, common in graphic technology and photography, it was felt that it would
be desirable to produce an image set in which some colours are permitted to be encoded close to the
boundary of the full colour gamut attained with surface colours. Furthermore, from the perspective
of colour management, it is advantageous if the images are referenced to illuminant D50, which is
the predominant reference illuminant used in graphic arts and photography, both for viewing and
measurement. For this reason, it has also become the predominant reference illuminant for most colour
management applications.
ISO 12640-4 provides a set of wide-gamut test image data encoded as Adobe RGB with a bit depth of
16 bits/channel. These data are optimized for viewing on a reference Adobe RGB display in the reference
Adobe RGB viewing environment (defined in the Adobe RGB (1998) Colour Image Encoding specification).
The images are designed to be used mainly on systems utilizing Adobe RGB as the reference encoding,
and as such are mainly applicable to the professional market and those systems for which the wide gamut
colour monitor is the “hub” device. Such workflows are popular among professional photographers,
and are increasingly used in the graphic arts. The Adobe RGB reference display colour gamut is closer
to typical offset printing gamuts than the sRGB reference display colour gamut. Adobe RGB encoded
images generally require much less aggressive colour re-rendering going to print than sRGB encoded
images, although this difference can necessitate colour re-rendering between Adobe RGB images and
sRGB images. The purpose of ISO 12640-4 is therefore to provide a test image data set with a larger
colour gamut than sRGB, related to the Adobe RGB wide-gamut display-referred colour space. The bit
depth of the natural images and synthetic images is 16 bits/channel.
The possible wide gamut colour encoding choices considered were Adobe RGB, opRGB (IEC 61966-2-5)
and ROMM RGB (ISO 22028-2). For ISO 12640-4, it was important that the images were well-colour-
rendered to a well-defined large gamut reference display, for which reason Adobe RGB was preferred
over the other two choices. With opRGB, the completeness of the colour rendering is left more ambiguous,
i.e. it is not as clearly output-referred, and the reference medium and viewing conditions are also
slightly different. ROMM RGB (ISO 22028-2) is clearly output-referred, but the reference medium is a
virtual reflection print (the ICC perceptual reference medium), so the image state is identical to that for
ISO 12640-3.
This part of ISO 12640 provides a set of scene-referred test image data encoded as RIMM RGB with a bit
depth of 16 bits/channel. These data are estimates of scene colorimetry obtained by capturing natural
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