ISO/IEC TR 19797:2004

Information technology — Office machines — Device output of 16 colour scales, output linearization method (LM) and specification of the reproduction properties

ISO/IEC TR 19797:2004 measures output and by the linearization method (LM).There is a table of output values and a graph for the first and linearized output. This method produces a linear relationship between the linear digital input data and the output data on a visual relative CIELAB scale for the colour primaries. The visual uniformity of overprint scales can be improved by this method. The method is applicable for systems that do not have colour management or as a linearization method for devices that could be used as a setup_state for colour management.

Technologies de l'information — Machines de bureau — Sortie de dispositif des échelles 16 couleurs, méthode linéaire de sortie (LM) et spécification des propriétés de reproduction

General Information

• Status: Withdrawn
• Publication Date: 19-Sep-2004
• Withdrawal Date: 19-Sep-2004
• ICS: 37.100.10 - Reproduction equipment
• Technical Committee: ISO/IEC JTC 1/SC 28 - Office equipment
• Drafting Committee: ISO/IEC JTC 1/SC 28/WG 5 - Office Colour
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 21-Sep-2018

Standards Content (Sample)

TECHNICAL ISO/IEC
REPORT TR
19797
First edition
2004-09-01

Information technology — Office
machines — Device output of 16 colour
scales, output linearization method (LM)
and specification of the reproduction
properties
Technologies de l'information — Machines de bureau — Sortie de
dispositif des échelles 16 couleurs, méthode linéaire de sortie (LM) et
spécification des propriétés de reproduction




Reference number
ISO/IEC TR 19797:2004(E)
©
ISO/IEC 2004

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ISO/IEC TR 19797:2004(E)
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©  ISO/IEC 2004
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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ii © ISO/IEC 2004 – All rights reserved

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ISO/IEC TR 19797:2004(E)
Contents Page

Foreword. iv
Introduction . v
1 Scope . 1
2 Normative References . 1
3    Terms and Definitions . 1
3.1  Definitions . 1
4    Overview: Six chromatic reproduction colours and 128 standard colours . 3
5    Colorimetric definition of the colour series in ISO/IEC-test charts . 6
6    Model output of 16 step LAB* colours and inverse correction . 8
6.1   Printer output of the ISO/IEC-test chart of this Technical report . 8
6.2   Simple model for standard and inverse image transformation . 9
7    Places for the Measurement, Transfer and Linearization (MTL) PS code . 10
8    Input–Output relationship of a colour laser printer (T) using the MTL code . 11
8.1  Output Linearization of the 128 standard colours on a laser printer . 11
8.2  First and linearized output for 8 colour series on a laser printer . 11
9 Basic Transformations between LAB* and cmy* . 15
Annex A: Output of 64 standard colours defined in different colour spaces . 18
Annex B: Information on web sites . 20
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ISO/IEC TR 19797:2004(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission)
form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC
participate in the development of International Standards through technical committees established by the respective
organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields
of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and
IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical
committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International Standards
adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the national bodies casting a vote.
In exceptional circumstances, the joint technical committee may propose the publication of a Technical Report of
one of the following types:
— type 1, when the required support cannot be obtained for the publication of an International Standard, despite
repeated efforts;
— type 2, when the subject is still under technical development or where for any other reason there is the future
but not immediate possibility of an agreement on an International Standard;
— type 3, when the joint 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).
Technical Reports of types 1 and 2 are subject to review within three years of publication, to decide whether they
can be transformed into International Standards. Technical Reports of type 3 do not necessarily have to be reviewed
until the data they provide 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 and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC TR 19797, was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 28, Office equipment.

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ISO/IEC TR 19797:2004(E)
Introduction

Purpose and justification
The method in this Technical Report produces a linear relationship between the linear digital input data and the
output data produced for a visual relative CIELAB scale. Using this method for a digital input value of 0.5 a mean
grey of 0.5 on a visual scale is produced. On the visual scale the values for white and black are 0 and 1 in relative
CIELAB space. The method has been already developed (there was a SC28 study period of one year, Project 18 of
the SC28 Berlin 2000 Plenary). Example files are on the Internet in various file formats (see SC28 Document
j28N493). The output will be within a visual tolerance of 6 CIELAB units independent of the file format used (see
graphs on page 13–15 and on BAM-Internet addresses listed in Annex B). For a given file format the CIELAB values
of the first output must be measured. The measured CIELAB data are included in a modified output file which
produces the linearized output which will be equally spaced in CIELAB. Various cases are given below:
1. PS (PostScript) file on a PS printer then the new PS output file on the PS printer produces the 16 step equally
spaced output.
2. PDF file on any printer then the new PDF output file is produced by the software Adobe Acrobat Distiller or
equivalent from a PS file. The PDF output file produces the 16 step equally spaced output.
3. GIF file on any printer then the new GIF output file is produced by the software Adobe Illustrator or equivalent from
a PS file. The GIF output file produces the 16 step equally spaced output.
The method is similar for other file formats and the output result is within a visual tolerance of 6 CIELAB units
independent of the file format used.
Advantages: If the CIELAB data of the first output are used then the linearization method (LM) leads to the same
relative CIELAB output within visual tolerances of 6 CIELAB values (1 step of 16 steps, see graphs on pages 13–
15) independent of e. g. application software, file format, printer driver and paper.
Remark: If the intended output is linearly spaced in relative CIELAB space (see ISO/IEC 15 775) then in most
cases the colour differences between the first and the linearized output and the intended output are reduced by a
factor 3 to 6.
© ISO/IEC 2004 – All rights reserved v

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TECHNICAL REPORT ISO/IEC TR 19797:2004(E)

Information technology — Office machines — Device output of
16 colour scales, output linearization method (LM) and
specification of the reproduction properties
1. Scope
A digital file is used to produce 16 step colour scales on a colour printer between the white paper and the 6
chromatic colours and black. The intended 16 step colour scales are defined in figures B4 and D4 of the ISO/IEC-
test charts for colour copiers according to ISO/IEC 15775. The digital file format may be PostScript (PS), Portable

document (PDF), GIF, HTM or equivalent. Within the different file formats the 16 step colour scales are defined by 16
digital values between 0 and 1, e. g. by 0, 1/15, 2/15 to 15/15 in CMY coordinates. The first output is measured and
by the linearization method (LM) of this Technical Report, a visually equally spaced output is produced in relative
CIELAB units, e. g. between the white paper and the six device colours and black. There is a table of output values
and a graph for the first and linearized output. This method produces a linear relationship between the linear digital
input data and the output data on a visual relative CIELAB scale for the colour primaries. The visual uniformity of
overprint scales can be improved by this method. The method is applicable for systems that do not have colour
management or as a linearization method for devices that could be used as a setup_state for colour management.
The aim of this method is to produce equal CIELAB spacing. The equal spacing of the steps achieved in the
linearization method may be adapted to various purposes. The accuracy and repeatability of this method is expected
to be within 6 CIELAB units. Other methods may be appropriate for applications requiring greater accuracy.
Note: Any first output can be used for this linearization method (LM) even though the first output depends e. g. on
application software, file format, printer driver, paper and other parameters.
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/IEC 15775: 1999, Information technology – Office machines – Method of specifying image reproduction of
colour copying machines by analog test charts – Realisation and application
ISO/CIE 10526:1991, CIE standard colorimetric illuminants
ISO/CIE 10527:1991, CIE standard colorimetric observers
CIE-pub. 15.2:1986, Colorimetry
ITU-R BT.709-2:1995, Parameter Values for the HDTV Standards for Production and International Program
Exchange
IEC/CIE 17.4:1987, International lighting vocabulary, 4th edition, Joint publication IEC/CIE
DIN 33866-1 to -5:2000, Information technology – Office machines – Colour image reproduction devices, Part 1:
Method of specifying image reproduction of colour devices by digital and analog test charts
3. Terms and Definitions
3.1 Definitions
For the purposes of this document, the following terms and definitions apply.
NOTE  The definitions are taken from ISO/IEC 15775 and IEC/CIE 17.4. The definitions are adapted to the
ISO/IEC Directives Part 2. The CIE/IEC definitions are adapted slightly to agree with the ISO/IEC Directives.
3.1.1
standard tristimulus values X, Y, Z and colorimetric parameters L*a*b*
describe the psychophysical colour
NOTE 1  Standard tristimulus values X, Y, Z are mostly obtained as an immediate result of a colour
measurement.
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ISO/IEC TR 19797:2004(E)
NOTE 2  As standard tristimulus values X, Y, Z only allow statements referring to equality of two colours, for
statements made beyond that, e. g. concerning the kind and size of colour differences, non-linear
transformations of X, Y, Z into other colorimetric parameters systems preferably into the colorimetric
parameters L*, a*, b* are necessary (compare CIE publ. 17.4)
NOTE 3  Within this Technical Report the abbreviation LAB* for the colorimatric parameters L*a*b* is used.
For relative CIELAB coordinates the abbreviation lab* is used.
3.1.2
colour difference ΔE*
ab
specifies the size of the difference between two colour stimuli
3.1.3
*-image (“star-image“)
includes colours defined by the colorimetric parameters L*a*b* of the CIELAB colour system.
NOTE  The *-image (“star-image“) includes colours (of the colour pixels or areas) which are defined either in
absolute (LAB*) or relative (lab*) coordinates.
3.1.4
*’-image (“star-prime-image“)
includes colours produced by a standard reproduction process of a colour device and is different than the *-image.
NOTE  The *’-image (“star-prime-image“) has different colorimetric parameters L*’a*’b*’ (*’-coordinates)
compared to the *-image (“star-image“) with L*a*b* parameters defined either in absolute (LAB*) or relative
(lab*) coordinates.
3.1.5
’*-image (“prime-star-image“)
is produced by the standard reproduction process of a colour device and is different than the *-image (“star-image“).
NOTE  The ’*-image (“prime-star-image“) is called the inverse image and includes L’*a’*b’* parameters
defined either in absolute (LAB*) or relative (lab*) coordinates.
3.1.6
standard image transformation
changes a *-image (“star-image“) into a *’-image (“star-prime-image“) (Fig. 1) or changes a ’*-image (“prime-star-
image“) into a *-image (“star-image“) (Fig. 2)
3.1.7
inverse image transformation
changes a *-image (“star-image“) into a ’*-image (“prime-star-image“) (Fig. 2) or changes a *’-image (“star-prime-
image“) into a *-image (“star-image“) (Fig. 1)
PostScript-
(PS-)image file:
LAB*- or lab*-file
CMY*- or cmy*-file
OLV*- or olv*-file
standard image inverse image
transformation transformation
* -image *’-image * -image
in ou
changes e. g. from changes e. g. from
LAB* to LAB*’ LAB* to LAB’*
or lab* to lab*’ or lab* to lab’*
PortableDocument-
(PDF-)image file:
LAB*- or lab*-file
CMY*- or cmy*-file
OLV*- or olv*-file
TR17979/IEBISI02
Figure 1: Standard and inverse image transformation
Fig. 1 shows that the standard image transformation changes a *-image (“star-image“) into a *’-image (“star-prime-
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ISO/IEC TR 19797:2004(E)
image“) and that the inverse image transformation changes a *’-image (“star-prime-image“) into a *-image (“star-
image“)

PostScript-
(PS-)image file:
LAB*- or lab*-file
CMY*- or cmy*-file
OLV*- or olv*-file
inverse image standard image
transformation transformation
* -image ’*-image * -image
in ou
changes e. g. from changes e. g. from
LAB* to LAB’* LAB* to LAB*’
or lab* to lab’* or lab* to lab*’
PortableDocument-
(PDF-)image file:
LAB*- or lab*-file
CMY*- or cmy*-file
OLV*- or olv*-file
TR19797/IEBIIS02
Figure 2: Inverse and standard image transformation
Fig. 2 shows that the inverse image transformation changes a *-image (“star-image“) into a ‘*-image (“prime-star-
image“) and that the standard image transformation changes a ‘*-image (“prime-star-image“) into a *-image („star-
image“)
4. Overview: Six chromatic reproduction colours and 128 standard colours
There is a variety of colour spaces which can be used for input and output. Any user has to spend a lot of time to
learn about the different spaces and to learn the relationship of the different spaces which depends on application.
cmyolvnw* default color space
CMYOLV hue circles
Y
hexagon Y
J
L O
L O
G R
W
C M
C M
B
V
V
three basic colors three mixed colors 4 and 6 colours
TR19797/E8370-12 TR19797/E8320-51
Figure 3: Six reproduction colours CMYOLV and four unique hue colours RJGB
Fig. 3 shows the six chromatic colours CMYOLV and Black N (=noir) and White W of standard offset printing (left).
The four unique hue colours RJGB are different from the six reproduction colours. Standard non fluorescent offset
paper was used to produce the analog ISO/IEC-test charts which are equally spaced in CIELAB coordinates.
There are productions by DIN and JBMIA (see Annex B.) in reflective and transparent mode. The German DIN-test
charts have been measured with the 45/0 measuring geometry for standard illuminant D65 and the CIE 1931
standard observer at BAM (Laboratory S.13). The mean colour difference of CMYOLV compared to the standard
data is 2.5 CIELAB, (see the standard DIN 33866-X and the International Standard ISO/IEC 15775).
Remarks: According to the International Standard ISO/IEC 15775 the letters j (=jaunne=yellow), r (red), g
(green), and b (blue) are reserved for the unique hues and the letters olv* (orange red, leaf green, violet blue) are
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ISO/IEC TR 19797:2004(E)
used with a star to indicate the linear relationship to CIELAB. The olv* coordinates are used for the reflective
colours and are used in a similar way as the coordinates rgb of the luminous television colours. The cmy*
coordinates are alternate coordinates compared to olv* (see Fig. 3 and Table 1 and 2).
All the 16 step colour series between white and the six chromatic colours CMYOLV (see Fig. 3) and black are equally
spaced in the CIELAB colour space. Laser printers produce the six chromatic colours using between three and six
colourants. The result is often similar to the six colours CMYOLV of the present analog ISO/IEC-test charts which
have been produced by standard offset printing.
The halftone screening of laser printers (or of offset printing) produce colours which are approximately on a line, e. g.
between White W and Cyan C in the CIELAB space. This is one basic assumption of the model colour space. In
practice the 16 colours between White and Cyan may slightly deviate by less then 3 CIELAB units from the line in
CIELAB space. This is much less than the 20 CIELAB unit spacing differences along the line W – C which printers
often produce. For the office applications the aim was to reduce the spacing differences of the 16 step series C – W
to below 3 CIELAB units. Then all Landolt-rings in the ISO/IEC-test chart output can be recognized. A non-critical
user may require that along the line W – C only the cyan coordinate of cmy* changes between zero and 1 in 15
digital steps of 1/15. The other coordinates are zero. In the alternate coordinate system olv* the Orange red
coordinate is zero and the other two change by equal amounts from zero to 1 in steps of 1/15 (see Table 2).
There were goals:
1) Linearization (equal CIELAB spacing) of the seven series W to CMYOLVN and
2) calculation methods to convert to coordinates cmy* and olv* from the CIELAB data of the standard (and the
analog samples) and vice versa.
Both goals have been achieved by PostScript code called MTL (MTL = Measurement, Transfer and Linearization). If
a device is linearized along the lines in CIELAB space then there are linear relationships between the coordinates
cmy*, olv*, and LAB* of the CIELAB colour space. The linear relations (and as a result a linear additive metric in
CIELAB space in each of the six sectors of Fig. 3) are used in the PS MTL code. Either the olv*, cmy*, or LAB* data
can be used with an ISO/IEC-test chart file to get the same output on a printer or monitor.
Table 1: Colour data of the 5 step colour series N – W for four input PS operators (N=noir=Black)
5 steps of grey series Colour space, colour space coordinates and PostScript operator
black - white (N - W) calculations according to ISO/IEC 15775:1999-12
Linear mixture between CIELAB l* CIE CMYN (CMYK) CMYN (CMYK) OLV (RGB)
black and white LAB* (absolute) w* = l* 000n* cmy0* www*
in CIELAB colour space LAB* setcolor setgray setcmykcolor setcmykcolor setrgbcolor
1,00 N + 0,00 W (black N) 18.01  0.50 -0.46 0,00 0,00 0,00 0,00 1,00 1,00 1,00 1,00 0,00 0,00 0,00 0,00
0,75 N + 0,25 W 37.36  0.13  0.84 0,25 0,00 0,00 0,00 0,75 0,75 0,75 0,75 0,00 0,25 0,25 0,25
0,50 N + 0,50 W 56.71 -0.24  2.15 0,50 0,00 0,00 0,00 0,50 0,50 0,50 0,50 0,00 0,50 0,50 0,50
0,25 N + 0,75 W 76.06 -0.61  3.45 0,75 0,00 0,00 0,00 0,25 0,25 0,25 0,25 0,00 0,75 0,75 0,75
0,00 N + 1,00 W (white W) 95.41 -0.98  4.76 1,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 1,00 1,00 1,00
TR19797/DESERCW2
Table 1 include four input PostScript (PS) operators which define the same achromatic colours black, three greys
and white. Between one and four input data values are necessary for the complete definition of the achromatic
colours depending on the colour space
Table 2: Colour data of 5 step colour series C – W for three input PS operators.
5 steps of colour series Colour space, colour space coordinates and PostScript operator
cyan blue - white (C - W) calculations according to ISO/IEC 15775:1999-12
Linear mixture between CIELAB CMYN (CMYK) OLV (RGB)
cyan blue and white LAB* (absolute) cmy0* (relative) olv* (relative)
in CIELAB colour space LAB* setcolor cmy0* setcmykcolor olv* setrgbcolor
1,00 C + 0,00 W (cyan blue C) 58.62 -30.62 -42.74 1,00 0,00 0,00 0,00 0,00 1,00 1,00
0,75 C + 0,25 W 67.82 -23.21 -30.86 0,75 0,00 0,00 0,00 0,25 1,00 1,00
0,50 C + 0,50 W 77.02 -15.80 -18.98 0,50 0,00 0,00 0,00 0,50 1,00 1,00
0,25 C + 0,75 W 86.21  -8.39  -7.11 0,25 0,00 0,00 0,00 0,75 1,00 1,00
0,00 C + 1,00 W (white W) 95.41  -0.98   4.76 0,00 0,00 0,00 0,00 1,00 1,00 1,00
TR19797/DESERCW1
Table 2 includes three input PostScript (PS) operators which define the same chromatic colour series between Cyan
blue and White. There are ISO/IEC-test chart files which use the different PS operators of Table 1 and 2.
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ISO/IEC TR 19797:2004(E)
0 cmyolvnw* default color space 0 cmyolvnw* color space
1 W 1
0,0
2 2
color space plane WON two printer device planes
W
0
3 3
1
4 4
WO N and WO N
w*
L* 2 1 2
5 5
o L*
6 3 6 6
4
7 7 7
0,2; 3 0,2; 3
5
8 8 8
o* o*
9 9 9
w w
A A A
Light-
B B B
C C C
ness D D D
0,4; 7 0,4; 6
E E E
(CIELAB)
F F F
O
0,6; A 0,6; 9
O O
2 1
w*
n*
o*
n*
0,8; D n 0,8; C
n*
o
C* C*
ab ab
1,0
N N
F
Chroma (CIELAB) Chroma (CIELAB)
TR19797/E6190-2Y, TR19797/E6190-2z,
Figure 4: Equal spacing in relative CIELAB in hue planes WO N for different devices x.
x
Fig. 4 shows the 16 step colour series equally spaced in relative CIELAB in the hue plane WON (left) for the
default device and in the hue planes WO N and WO N for two other different devices. The CIELAB chroma C* of
1 2 ab
the devices 1 and 2 is larger or smaller (right) compared to the default chroma (left) but the relative spacing in
CIELAB is equal in all cases. The dark dots show the 16 step colour series which this Technical Report will produce
on a printer. The coordinates used in this Technical Report are
n* (relative blackness)
n* changes from 0 to 1 (decimal) or from 0 to F (hexadecimal, 4bit) for the series White W to Black N (W–N).
o* (relative orange redness of the whitish series w)
w
o* changes from 0 to 1 (decimal) or from 0 to F (hexadecimal, 4bit) for the series White W to Orange red O (W–O).
w
There are some other coordinates, e. g. relative whiteness w* and relative orange redness of the blackish series o*
n
in Fig. 4 which have simple relationships to the above two relative coordinates and also to the CIELAB coordinates.
Remark 1: The method of this Technical Report is not designed to produce equal steps for the series O–N, O –N
1
and O –N (hollow circles) but experimental and theoretical studies show that the spacing of this series is close to
2
equal relative spacing if the method of this Technical Report is used.
Remark 2: For many applications the relative spacing of the whitish series W–O is more important compared to
the blackish series O–N. For instance both for best differentiation of 16 colour steps and low toner consumption
the series W–O is appropriate.
Remark 3: The ISO/IEC-test charts according to ISO/IEC 15775 include the 16 step default colour series W–O
and W–N for the test of colour copiers.
It is within the scope of this Technical Report that the relative spacing in CIELAB can be made the same for all
devices as shown in Fig. 4. Then the recognition of e.g. the 16 step series W–O, W–O and W–O is constant as long
1 2
as the chroma of the colour O is not too small. The colour difference of the default series W–O is about 120. For 16
2
steps this means that there is a colour difference in CIELAB of 8 (=120/15) between two adjacent colour steps. The
perception threshold for the colour difference of colours side by side is about 1 CIELAB unit and for colours spacially
separated about 3 in CIELAB units. For printers in the worst-case a reduction of the chroma of O to 50% compared
2
to the default chroma of O may be assumed. Even in this worst-case the colour difference (about 5 = 75/15 in
CIELAB) is much above threshold for both adjacent and separated colour steps for the colour series between W–O .
2
The ISO/IEC-test charts 2 and 4 according to ISO/IEC 15775 include 8 colour series of 16 steps colours in Fig. B4
and D4. There are 128 standard colours which are shown in Fig. 5
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BAM registration: 20030101-DE95/10L/L95E00NP.PS/.PDF BAM material: code=rha4ta
application for measurement of monitor (Yr=2.5) and printer output
See for similar files: http://www.ps.bam.de/DE95/DE95.HTM
Information and Order: http://www.ps.bam.de Version 2.0, io=0,0
ISO/IEC TR 19797:2004(E)
.
-8 V L O Y M C -8
www.ps.bam.de/DE95/10L/L95E00NP.PS/.PDF; start output
N: No Output Linearization (OL) data in File (F), Startup (S) or Device (D)
C V
C
c000*
M
0m00*

M L
Y
00y0*
N
000n*
Y O
0123456789A B C D E F

O
0my0*
O Y
L
c0y0*

V
L cm00* M
N
cmy0*
0123456789A B C D E F
*=input

V C

Picture B4 and D4: 16 equidistant steps B4: W-C, W-M, W-Y and W-N; D4: W-O, W-L, W-V and W-N(CMY); Use of PS operator; B4: cmy0* / 000n* setcmykcolor; D4: cmy0* setcmykcolor (only)
Fig. B4 of ISO/IEC-test chart 2 and ISO/IEC 15775 and input: cmyn* setcmykcolor
Fig. D4 of ISO/IEC-test chart no. 4; TR ISO/IEC 24705; output: no change compared to input
-8 -8
-6 C M Y O L V -6
Figure 5: First output of 128 standard colours defined in this ISO/IEC Technical Report
Fig. 5 shows the 128 standard colours which can be made equally spaced in CIELAB for hardcopy output for any
device using this Technical Report. Equal relative spacing of the 8 series is possible on any printer using any
computer operating system, any file format and any application as far as we know. The digital file of this Technical
Report uses relative cmy* colour coordinates together with the PostScript operator setcmykcolor to verify this
property for the different parameters.
Remark 1: Fig. 13 of this Technical Report will show a linearized output of the 8 colour series.
Remark 2: A list of files which include the original files of Fig. 5 and Fig.13 is at
http://www.ps.bam.de/DE95/DE95.HTM
5. Colorimetric definition of the colour series in ISO/IEC-test charts
Four analog ISO/IEC-test charts according to ISO/IEC 15775 are designed for the test of colour copiers. The
International Standard ISO/IEC 15775 includes the L*a*b* reference data of the CIELAB space and the
corresponding cmy* data of the colours used in the test charts.
Table 3: Intended printing (PR) and television (TV) colours and comparison
Basic Intended CIELAB data Intended CIELAB data CIELAB differences   CIELAB-
test CMYN (ISO 2846−1) RGB (ITU-R BT.709-2) of test colours   test colour
colour Reference (r) Output (o) Difference (o−r)   difference
name L* a* b* L* a* b*  L*∆∆∆  a*  b*   E*∆
r r r o o o o−r  o−r  o−r   ab
  C 58.62 −30.62 −42.74 86.88 −46.17 −13.56 28.26 −15.54 29.18 43.5
  M 48.13 75.2 −6.79 57.3 94.35 −20.7  9.17 19.15 −13.9 25.38
  Y 90.37 −11.15 96.17 92.66 −20.7 90.75  2.29 −9.54 −5.41 11.22
  O 47.94 65.31 52.07 50.5 76.92 64.55  2.56 11.61 12.48 17.24

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