ISO/TR 16066:2003
(Main)Graphic technology — Standard object colour spectra database for colour reproduction evaluation (SOCS)
Graphic technology — Standard object colour spectra database for colour reproduction evaluation (SOCS)
ISO/TR 16066:2003 provides a database of typical and difference sets of existing object colour spectral data that are suitable for evaluating the colour reproduction of image input devices. It also includes the spectral reflectance and transmittance source data from which these data sets have been derived.
Technologie graphique — Base de données de spectres de couleurs d'objets normalisée pour l'évaluation de la reproduction des couleurs (SOCS)
General Information
Relations
Standards Content (Sample)
TECHNICAL ISO/TR
REPORT 16066
First edition
2003-03-15
Graphic technology — Standard object
colour spectra database for colour
reproduction evaluation (SOCS)
Technologie graphique — Base de données de spectres de couleurs
d'objets normalisée pour l'évaluation de la reproduction des couleurs
(SOCS)
Reference number
©
ISO 2003
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2003
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 2003 — All rights reserved
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Standard object colour spectra . 1
2.1 Object categories and sample selection . 1
2.2 Typical set samples and difference set samples. 4
3 Use of the colour spectra database . 5
3.1 Use of typical sets. 5
3.2 Use of difference sets. 7
4 Permissions. 8
Annex A (informative) Spectral reflectance and transmittance source data. 9
Annex B (normative) Typical set selection method for artificial colour groups. 27
Annex C (normative) Typical set selection method for non-skin colour, natural colour groups . 29
Annex D (normative) Typical set selection method for skin groups. 31
Annex E (normative) Difference set selection method. 32
Annex F (informative) Correspondence between typical/difference samples and original collected
data samples . 33
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 exceptional circumstances, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for example), it may decide by a
simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely
informative in nature and does not have to be reviewed until the data it provides are considered to be no
longer valid or useful.
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/TR 16066 was prepared by Technical Committee ISO/TC 130, Graphic technology.
The TC 130 Japanese National Committee prepared this database, and their efforts have made this Technical
Report possible. The original form of this report was published as a technical report TR X 0012 by the
Japanese Standards Association in Japanese in December 1998.
iv © ISO 2003 — All rights reserved
Introduction
The simplest way to evaluate the colour reproduction of colour image input devices is to input images of objects
whose colours are exactly known and then to compare the pixel values to exact ones. For that purpose, input
colour target standards have been already established in ISO 12641:1997, Graphic technology — Prepress
digital data exchange — Colour targets for input scanner calibration. Evaluation becomes more complicated,
however, when we consider metamers.
The perceived colours of a pair of objects are referred to as metamers if, under a particular illumination, they
have the same tristimulus values even though they are spectrally different. The spectral pairs of such objects
may be used to advantage in the assessment of differences among lighting conditions. If, for instance, a pair
of spectra yield the same tristimulus values X, Y, Z under CIE illuminant D50, the difference between the two
perceived colours of the pair of spectra as measured in the field under a different illumination is referred to as
a metameric index, which can be used as a measure of the non-conformance of that illumination to D50.
While it may be sometimes preferable, e.g. for standards purposes, to use artificial pairs of perceived colours,
i.e. those not coming from natural objects, natural metameric pairs have the advantage that one can assess
the effect of non-standard lighting for a particular lighting condition. One may find, for instance, that a
particular light source leads to unacceptably large deviations in skin tones, whereas the same source is quite
acceptable for furniture colours.
Definitions with respect to metameric indices and the procedures for their evaluation are described in the
following CIE publications:
CIE 15.2, Colorimetry, 2nd ed. (1986) (Contains Special Metamerism Index: Change in Illuminant)
CIE 51.2, A method for assessing the quality of daylight simulators for colorimetry (1999)
CIE 80, Special metamerism index: Change in observer (1989)
It can also be useful to consider metamers in the evaluation of such colour image input devices as colour
scanners and digital cameras, which, though designed to capture images in a way similar to that of the human
visual system (HVS), nonetheless deviate enough from HVS sensitivity so that colour reproduction of sensed
colours in display devices or print outputs are significantly different from that desired, even when the
illumination conditions of the original human observation of an object have been recreated for the observation
of the output image.
To evaluate deviations due to variations in light sources and/or sensor sensitivities under actual conditions, it
is useful to know the range of spectral differences in existing objects. Committee members have created an
exhaustive collection of colours of existing objects, a database containing more than 50 000 items. This report
details the extraction from the data of 365 colour samples and their classification into sets, of which there are
two types, “typical sets” and “difference sets”. “Typical sets” refers to sets of typical spectral reflectances and
transmittances of objects as classified into a number of different categories. “Difference sets” refers to sets of
metamers whose tristimulus values are roughly typical but whose spectral values are significantly non-typical.
The entire original collection of more than 50 000 spectral data items is included, in electronic form, as part of
this Technical Report in the data directory SourceData as described in Annex A.
TECHNICAL REPORT ISO/TR 16066:2003(E)
Graphic technology — Standard object colour spectra database
for colour reproduction evaluation (SOCS)
1 Scope
This Technical Report provides a database of typical and difference sets of existing object colour spectral data
that are suitable for evaluating the colour reproduction of image input devices. It also includes the spectral
reflectance and transmittance source data from which these data sets have been derived.
2 Standard object colour spectra
2.1 Object categories and sample selection
2.1.1 Categories and groups
The following categories and subcategories were first established:
(1) Photographic materials
a. Transparencies
b. Reflection prints
(2) Offset prints
(3) Computer colour prints
a. Dye sublimation printer
b. Electrostatic printer
c. Ink-jet printer
(4) Paint (not for art)
(5) Paints (for art)
a. Oil paints
b. Water colours
(6) Textiles
a. Synthetic dyes
b. Plant dyes
(7) Flowers and leaves
(8) Outdoor scenes (Krinov data except for flowers and leaves)
(9) Human skin
a. Bare North Asian skin
b. Foundation-applied North Asian skin
c. Bare South Asian skin
d. Foundation-applied South Asian skin
e. Bare Caucasian skin
f. Bare Negroid skin
Spectral reflectance/transmittance data were then collected for more than 50 000 items falling into these
categories/subcategories.
Categories (1) to (5) and subcategory (6)a are for artificial colours, while subcategory (6)b and categories (7)
to (9) are for natural colours. Typical sets and difference sets were established from 365 samples in this
database. A typical set is a set of representative spectral data of colour objects, while a difference set is a set
of metamers whose colour under D65 illuminant is similar to typical set samples but differs significantly from
them spectrally. Samples for the typical and difference sets were selected as shown in Table 1. The manner
of selecting typical samples depended on whether colours were artificial or natural. In most artificial colour
groups, all colours are synthesized by mixing three or four colorants, and distributed almost uniformly in their
colour gamut. Colours in the paint (not for art) and paints (for art) categories, however, are synthesized by
mixing more than four colorants, and these categories were dealt with in the same manner as with natural
colours. Selection strategies are described in following subsections.
Table 1 — Numbers of selected typical/difference set colour samples
Group Typical sets Difference sets
Photo (transparency) 15 15
Photo (reflection print) 15 15
Offset prints 15 15
Dye sublimation printer 15 15
Electrostatic printer 15 15
Ink-jet printer 15 15
Textiles (synthetic dyes) 15 15
Flowers/grasses/leaves (includes 25 25
Krinov’s grasses and leaves)
Paint (not for art) 15 —
Oil paints 15 —
Water colours 15 —
Textiles (plant) 15 —
Non-grass/leaf Krinov 15 —
Bare North Asian skin 5 —
FD-applied North Asian skin 5 —
Bare South Asian skin 5 —
FD-applied South Asian skin 5 —
Bare Caucasian skin 5 —
Bare Negroid skin 5 —
Total 365
2 © ISO 2003 — All rights reserved
NOTE ‘Foundation’ is a cosmetic used as a base for facial make-up. However, in this Technical Report, ‘foundation
applied skin’ means skin that is not bare, but covered with foundation and/or face powder.
2.1.2 Typical set selection for artificial colour groups
There are seven artificial colour groups in Table 1: photographic transparency, photographic reflection prints,
offset prints, dye sublimation printer, electrostatic printer, ink-jet printer, and textiles (synthetic dyes). Colour
samples can be obtained for every hue in these groups.
Colorants can be expected to vary within any one group, as, for example, among the many products of
different photographic prints material manufacturers. Spectral reflectance measurements were carried out for
several representative products among them. Statistical analysis was carried out on the measurement data,
and the product whose characteristics most closely approximated the statistical average for the products as a
whole was determined to be a typical colour product. A mathematical explanation for this is found in Annex B.
From a large number of colour samples for a typical product, fifteen samples were selected whose colours are
nearest to pre-determined basic colours, which consist o
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.