ISO 12640-1:1997

SLOVENSKI STANDARD
SIST ISO 12640-1:2008
01-junij-2008
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Graphic technology – Prepress digital data exchange – Part 1: CMYK standard colour
image data (CMYK/SCID) / Note: CD-ROM
Ta slovenski standard je istoveten z: ISO 12640-1:1997
ICS:
35.240.30 Uporabniške rešitve IT v IT applications in information,
informatiki, dokumentiranju in documentation and
založništvu publishing
37.100.99 'UXJLVWDQGDUGLY]YH]L] Other standards related to
JUDILþQRWHKQRORJLMR graphic technology
SIST ISO 12640-1:2008 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 12640-1:2008

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SIST ISO 12640-1:2008
INTERNATIONAL IS0
STANDARD 12640
First edition
1997-l 2-15
Graphic technology - Prepress digital data
CMYK standard colour image
exchange -
data (CMYWSCID)
Technologie graphique - khange de don&es numkriques de
Don&es d’images en couleur CMYK normales
pr&mpression -
(CM YWSCID)
Reference number
IS0 12640: 1997(E)

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SIST ISO 12640-1:2008
ISO12640:1997(E)
Contents
. . .
. . . . . . . . . .‘. 111
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . 1V
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Normative references . . . . . . . . . . . . . . . . . . . . . . . 1
................
Definitions . 1
.......................
Requirements . . . . . . . . . . . . . . . . . . . . . . 2
Data description and definition . . 2
Electronic data . . 4
Annexes
17
A Standard colour image digital data . . . . . .
B Check-sum data . . . . . . . . . . . . . . . . . . . . . 21
C Typical TIFF/IT file headers used on CD-ROM . . . . . . . . . . . . . . . . . . . 23
0 IS0 1997
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 the publisher.
international Organization for Standardization
Case postale 56 l Cl-l-121 1 Geneve 20 l Switzerland
Internet central @ iso.ch
c=ch; a=400net; p=iso; o=isocs; s=centraY
x.400
Printed in Switzerland
ii

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SIST ISO 12640-1:2008
IS0 12640:1997(E)
@ IS0
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards bodies (IS0 member bodies). The work of preparing
International Standards is normally carried out through IS0 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. IS0 collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
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.
International Standard IS0 12640 was prepared by Technical Committee
ISO/TC 130, Graphic technology.
Annexes A and B form an integral part of this International Standard. Annex C is
for information only.

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SIST ISO 12640-1:2008
@ IS0
IS0 12640: 1997(E)
Introduction
The initial technical content of this International Standard was coordinated by the
Image Processing Technology Standard Committee in Japan as input to, and in
coordination with, ISO/TC liO/WG2.
Need for standard digital test
The following figure shows a block diagram of the typical functions that may be
- -
involved in the preparation of images for graphic arts reproduction. Not all current
systems have coding or communication functions, and the read/write operations are
frequently executed by devices installed at the same site. However, when
considering the need for and development of these test images, the expert group
considered systems that do include all the functions of image processing, data
storage, encoding and transmission of data.
9
ecu ’
Image ’
Image
Encoder
Scanner
Processor
E
A
B C D
Communication
Network
B’ D
A C’
, -
. ecu ’
Proof Image
Image
*
Decoder
Processor
Writer
.
High-quality image reproduction and transmission system
The typical systems evaluation path would normally involve scanning a test image at
- e
point-A and monitoring the characteristics or change in characteristics of that image
at each stage of the system. However, the differences between scanners make it
nearly impossible to repeatably create the same data file from a reference image on
film. Such differences would make it impossible to compare other performance
characteristics between systems or between sites.
To resolve this, a set of suitable test images was created that can be provided in
digital form, to be used at every site regardless of the type of equipment used.
Performance of any stage of the process (except of course input scanning) can thus
be evaluated by comparing the image data before and after processing or by
-
s
evaluating the effect of different processes on the final output. IS0 1264 1, C;raphic
technology - Yrepress digital data exchange - Colour targetsfbr input scanner
calibration, provides targets for the evaluation and/or characterization of the
scanning process itself.
iv

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SIST ISO 12640-1:2008
IS0 12640: 1997(E)
0 IS0
The following are examples of tvpical uses of these images.
- The objective comparison of colour output systems such as printing, colour
proofing, and colour facsimile. These comparisons may include evaluation of
e
image processing times and system efficiencies as well as image quality, colour
fidelity, etc.
- The evaluation of the effect or efficiency of coding schemes, data compression,
*
and/or data transmission.
- The characterization of printed output from both traditional processes and direct
digital output devices.
It is believed that these images will find application in many industries, in addition
to graphic arts, where quality would be influenced bv data transmission, image
-
processing, storage, and recording.
Characteristics of test images
The performance of any colour reproduction system will be evaluated both
. w
subjectively (by viewing the final output image) and objectively by measurement of
control elements. This dictated that the test images include both natural scenes
(pictures) and control targets.
Because the results of subjective image evaluation are strongly affected by the
-
image content it was important to insure that the natural images were of high quality
and contained diverse subject matter.
Development of digital test images
A desirable image
survey was conducted of all TC 130 member countries to identify
co ntent and to solicit submission of suitable images for considerati .on.
The image set that resulted consists of 8 natural and 10 synthetic images. The
natural images include flesh tones, images with detail in the extreme highlights or
shadows, neutral colours, colours in the brown and wood tone area which are
difficult to reproduce. memory colours, complicated geometric shapes, fine detail,
*
and highlight and shadow vignettes.
The synthetic images selected include resolution charts, uniform vignettes in both
the primary and secondary colours, and a physical representation of the CMYK data
- e -
set defined in IS0 12642 for the characterization of 4-colour process printing.
The eight colour pictures were converted to CMYK digital data using a graphic arts
colour scanner with scanning parameters optimized for each image to allow
common reproduction aims. The five resolution charts and five colour charts were
generated electronically.
w
In order to meet the needs of the widest graphic arts community, two resolution/data
encoding combinations were selected for all images. Both are pixel interleaved data
with the data origin at the upper left of the image, as viewed naturally, and
organized by rows. The first set has a data spacing of 16 pixels per millimetre and a
data encoding of 28 to 228 representing 0% to 100% printing values. The second
set has a data spacing of 12 pixels per millimetre (approximately 300 pixels per
inch) encoded with digital data of 0 to 255 representing 0 to 100°% printing values.
These data are available on a CD-ROM formatted in accordance with IS0 9660.
The file format is TIFF/IT as defined in IS0 12639. This file format is also
compatible with TIFF Revision 6, Section 16, and can be imported and manipulated
as necessary by a wide variety of commonly used imaging software packages on
platforms in general use in the industry.
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SIST ISO 12640-1:2008
IS0 12640: 1997(E) 0 IS0
It should be noted that the grey balance of these images is self-consistent, but
may not be optimum for any particular printing condition. The user is urged to
use these images ‘as is’ as a tool to understand the reproduction characteristics of
various processes. There is no ‘correct’ reproduction.
vi

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SIST ISO 12640-1:2008
INTERNATIONAL STANDARD @ IS0 IS0 12640:1997(E)
Graphic technology - Prepress digital data exchange - CMYK
standard colour image data (CMYIUSCID)
1 Scope 3 Definitions
This International Standard specifies the CMYK digital For the purposes of this International Standard, the
data that represents a set of standard colour images to be following definitions apply.
used for evaluation of changes in image quality during
coding, image processing (including transformation, 3.1 check sum: Sum of the digits in a file that can be used
compression and decompression), film recording or print-
to check if a file has been transferred properly.
ing which can be used for research, development, product
NOTE 1 Often, only the least significant bits are summed.
evaluation, and process control.
3.2 colour sequence: Order in which colours are printed
on a substrate or stored in a data file.
2 Normative references
3.3 colour value: Numeric values associated with each of
The following standards contain provisions which, through
the pixels.
reference in this text, constitute provisions of this
lnternational Standard. At the time of publication, the
3.4 data range: Range of numeric digital values over
editions indicated were valid. All standards are subject to
which the data is specified.
revision, and parties to agreements based on this
International Standard are encouraged to investigate the
3.5 dot percentage: Percentage of an area covered by
-
possibility of applying the most recent editions of the
- -
halftone dots, ranging from 0% to 100%.
standards indicated below. Members of IS0 maintain
registers of currently valid International Standards.
NOTE 2 The lightest areas of an image are represented by the
smallest coverage, at or near 056, while the darkest image areas
IS0 9660: 1988, b$tirmation processing - Volume andBle
consist of dots near maximum coverage of 100%.
structure of CD-ROMfor infLmzation interchange.
3.6 global colour change: Change in the relationship of
ISOIIEC 10149: 1995, Information technology - Data
colours in an image applied consistently to all parts of the
interchange on read-only 120 mm optical data disks
image as contrasted to a local colour change where selected
(CD-ROM).
spatial areas of an image are changed separately from the
rest of the image area.
IS0 12639: 1), Graphic technology - Prepress digital
data exchange - Tag imageJile format for image
3.7 input colour scanner: Device capable of converting
technology (TIFF/IT).
the light reflectance or transmittance of a photographic (or
other hardcopy) sample into an electronic signal - where the
IS0 12642: 1996, Graphic technology - Prepress digital
electronic signal is arranged to have an organized
data exchange - Input data for characterization of 4-
relationship to the spatial areas of the image evaluated.
colour process printing.
3.8 orientation: Specifies the origin and direction of the
IS0 14672: l), Graphic technoZoguy - Preprem digital
first line of data, with respect to the image content as
data exchange - Statistics of SCID images.
1) To be published
1

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SIST ISO 12640-1:2008
@ %SO
IS0 12640: II 997(E)
The synthetic images consist of resolution charts and colour
viewed by the end user. The codes used to specify
-
charts. They are identified as S 1 to S 10 for the primary set
orientation are contained in IS0 1263 9.
and S 1A to SlOA for the alternate set.
pixel: Smallest element
3.9 in a digital imaging system.
5.2.1 Natural images
pixel interleaving: Colour data organized such that
3.10
The characteristics and @pica1 usage of the natural images
the cyan, magenta, yellow and black colour values for one
s
are contained in table 1. The descriptive names of these
pixel are followed by the same sequence of colour values
images are given following the identification code. Figure
for the next pixel. yhe specific order of colours is
1 shows reduced monochrome reproductions of the natural
determined by the ColorSequence tag as defined in IS0
12639. - images. Additional information concerning the statistical
characteristics of these images is contained in IS0 14672.
NOTE 3 Other forms of colour data interleaving are line and The natural images have the following characteristics:
plane.
Picture size
Primary set:
4 Requirements 2 560 pixels(long side) by 2 048 pixels(short side)
-
Alternate set:
This International Standard consists of the data recorded on 1 920 pixels(long side) by 1 536 pixels(short side)
-
the CD-ROM bearing the title “IS0 12640, Graphic
technology - Prepress digital data exchange - CMYK NOTE 4 This corresponds to a physical image size of 160 mm by
128 mm or 6,3 in by 5,04 in when rendered at the recommended
standard colour image data (CMYIUSCID) - Annex A -
resolution of 16 pixels/mm for the primary set or 12 pixels/mm for
Standard colour image digital data” which is part of this
the alternate set.
International Standard. The image characteristics of these
data are described in clause 5 and the electronic data
Interleaving :
structure in clause 6.
Pixel interleaving
Colour sequence:
5 Data description and definition
C (Cyan), M (Magenta). Y (Yellow) and K (Black).
-
5.1 Data resolution
Colour values
Primarv set:
The data set is provided at two different combinations of
&bit binary data scaled linearly with respect to the
digital data encoding range and resolution. The primary set
printing dot percentage, where-a digital code value of
has a data range of 28 to 228 corresponding to dot -
28 corresponds to 0% and 228 corresponds to 100% .
percentages of 0% to 100% and has a data spacing of 16
Alternate set:
pixels/mm (406 pixels/in) at the intended image size (128
8-bit binary data scaled linearly with respect to the
mm by 160 mm). The alternate set has a data range of 0 to
printing dot percentage, where a digital code value of
255 corresponding to dot percentages of 0% to 100% and
0 corresponds to 0% and 255 corresponds to 100% ,
has a data spacing of 12 pixels/mm (305 pixels/in) for the
same image size.
Image data orientation :
Horizontal scanning starting from top left and ending at
The alternate set was generated from the primary set by
-
-
bottom right.
means of an analytical transform rule. Both sets contain the
same pictures except that each image in the alternate set
NOTE 5 The encoding ofthese data in the headers ofthe
has “IS0 300” in small size text added to the top of the
individual files is illustrated in annex C, and is in accordance with
the formats specified in IS0 12639.
image in order to distinguish it from the primary set that has
“IS0 400”.
5.2.2 Synthetic images - resolution charts
5.2 Data set definition
Synthetic images, S 1 to S5 and S 1A to S5A, are resolution
-
charts. These are used to evaluate the resolving power of
Each set of primary and alternate standard colour image
output devices, registration accuracy of separations, moire
data consists of eight natural (photographed) images and
and aliasing effects. There are five patterns consisting of a
ten synthetic images created digitally by a computer. The
quarter of a sunrise or star target with each ray separated by
natural images in the primary set are identified as Nl to N8,
*
-
4 degrees. Each pattern is 400 pixels square for the
respectively. The letter “A” is added to the images in the
primary set and 300 pixels square for the alternate set. The
alternate set (e.g. NlA). Each of these also has a
*
size achieved at these resolutions is 25 mm square. The
descriptive name derived from the picture content (e.g.
numeric values of all four separations are identical.
Cafeteria).
2

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SIST ISO 12640-1:2008
0 IS0 IS0 12640: 1997(E)
Table 1 - Natural images
Name Aspect Characteristics
N 1 Portrait Portrait Closeup image of model used to evaluate the reproduction
of human skin tones.
N2 Cafeteria Portrait Image with complicated geometric shapes. Suitable for
evaluating the result of image processing.
N3 Fruit Basket
Landscape Image of a fruit basket, cloth and wood used to evaluate the
reproduction of brown colours and fine texture.
N4 Wine and Landscape Image of glassware and silverware used to evaluate the
Tableware reproduction characteristics of highlight tones and neutral
colours.
N5 Bicvcle
Portrait Image of a (penny-far-thing) bicvcle. resolution charts and
s _
other items containing fine detail used to evaluate the
sharpness of reproduction and the results of image
processing.
N6 Orchid Landscape Image of an orchid with background vignettes used to
evaluate reproduction of highlight and shadow vignettes.
N7 Musicians
Landscape Image of three women used to evaluate the reproduction of
different skin tones and fine image detail.
N8 Candle Landscape “Low-key” image of a room scene containing
*
miscellaneous objects used to evaluate dark colours.
particularlv browns and greens.
-
The values of S 1 and S 1 A change sinusoidallv, so that the
52.3 Synthetic images - colour charts
v
smoothness of density change, and reproduction of middle
tones can be evaluated. The Sl and S 1A patterns were Svnthetic images S6 and S6A are 2 5 12 pixels bv 3 048
generated to complete one cycle ever-v 4 degrees. The pixels and 1 884 pixels by 2 286 pixels. respectivelv and
- c -
relation between the pixel value and the angle, 8, measured
contain 8 strips, each of which is a continuous vignette and
counter-clockwise from the X-axis is expressed as: is 256 pixels bv 3 032 pixels and 192 pixels bv 2 274
pixels, respectivelv. The vignettes range from 0% to 100%
Tone value (%) = 50 + 50 sin[( 90 l 8 )“I dot area for each of the four separation colours and the
two- and three-colour combinations of cyan, magenta and
The synthetic images S2 and S2A are binary yellow. These features are shown in figures 4 and 5. S6
- w
representations of S 1 and S 1A created by causing all values and S6A also contain the text “IS0 400” and “IS0 300”
of SO’/0 or less to be recorded as O”/o and all values above around the centre of the white area between K and R.
50% to be recorded as 100%. S3 and S3A are similar
binary images with the values less than 50% recorded as Synthetic images S7 to S 10 (and S7A to S 1OA) together
provide the image elements defined in IS0 12642. The
100% and those greater than 50% as 0% (the reverse of S2
grouping of these elements has been chosen to allow them
and S2A). S4 (S4A) and S5 (S5A) are created in a similar
...