ISO 12641:1997
(Main)Graphic technology — Prepress digital data exchange — Colour targets for input scanner calibration
Graphic technology — Prepress digital data exchange — Colour targets for input scanner calibration
Technologie graphique — Échange de données numériques de préimpression — Cibles de couleur pour étalonnage à l'entrée du scanner
Grafična tehnologija - Izmenjava digitalnih podatkov v grafični pripravi - Barvne tablice za umerjanje skenerjev
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IS0 12641:1997(E)
Contents
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
1
1 Scope .
......................................... 1
2 Normative references
................................................. 1
3 Definitions
2
...............................................
4 Requirements
2
4.1 Targetdesign .
......................................... 3
4.2 Transmission targets
7
............................................
4.3 Reflection targets
10
...........................
4.4 Allowable tolerances on patch values
................ 11
4.5 Spectral measurement and calorimetric calculation
............................................. 11
4.6 Data reporting
11
............................................
4.7 Datafileformat
.......................................... 12
4.8 Useable target life
Annexes
....................... 13
A Gamut mapping - computational reference
........................................... 14
B Application notes
............................................ 17
C Data file format
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 CH-1211 Geneve 20 l Switzerland
Internet central @ iso.ch
x.400 c=ch; a=40Onet; p=iso; o=isocs; s=central
Printed in Switzerland
ii
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@ IS0
lSO12641:1997( E)
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 12641 was prepared by Technical Committee
ISO/TC 130, Graphic technology.
Annexes A, B, and C of this International Standard are for information only.
0.”
Ill
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IS0 12641 :1997(E) @ IS0
Introduction
The technical requirements of this International Standard are identical to the
American National Standards IT8.7/1- 1993 and IT8.7/2- 1993. These documents
resulted from the joint efforts of an international industry group that included
participants representing a broad range of prepress vendors, film manufacturers, and
users. This group, initially identified as the DDES (Digital Data Exchange
Standards) Committee, later became the founders of the ANSI IT8 (Image
Technology) accredited standards committee which is responsible for electronic data
exchange standards in graphic arts prepress.
Purpose of this International Standard
Colour input scanners do not all analyze colour the same way the human eye does.
These devices are designed to optimize the signal generated when typical materials
are scanned. Colour reflection and transparency products use various combinations
of proprietary dye sets to achieve visual responses that simulate the colour appea-
rance of natural scene elements. The ability to achieve the same colour appearance
from different combinations of dyes is referred to as metamerism. Because both
photographic dyes and input scanner sensitivities vary from product to product, there
is a variability in the input scanner response to metameric colours produced by the
various materials. The intent of this International Standard is to define an input test
target that will allow any colour input scanner to be calibrated with any film or paper
dye set used to create the target. This International Standard is intended to address
the colour reflection and transparency products which are generally used for input to
the preparatory process for printing and publishing.
The target was designed to be useable for calibration by visual comparison and as a
numerical data target for electronic systems and future development. The target
design made use of a uniform colour space to optimize the spacing of target patches.
The tolerances developed for individual coloured patches meet the values needed for
both numerical and visual analysis.
Design of the target
The CIE 1976 (L*a*b*) or CIELAB colour space was chosen as the space to be used
for the design of the colour calibration target. Uniform spacing in hue angle,
lightness and chroma, and tolerancing in terms of differences in these parameters
(AEzb) is believed to provide a reasonable distribution of coloured patches in the
most effective manner. Although CIELAB was defined with reference to reflection
viewing conditions, tolerancing in terms of vector differences (AE,*& does provide a
reasonable error estimate for transmission materials as well, although the uniformity
of the space is dependent upon the conditions of viewing.
The design goal was to define a target that would have, as its main part, as many
common coloured patches as was practical, regardless of the dye set used. It was
iv
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0 IS0
IS0 12641:1997(E)
determined that the remainder of the target should define the unique colour
characteristics of the particular dye set used to create a specific target; the values for
each target patch should be established using a common procedure.
To provide a reasonable measure of the colour gamut that is within the capability of
modern colour papers and films, all manufacturers of these products were invited to
provide colour dye data along with the necessary minimum and maximum density
data for each of their image forming colour dye sets. Data were provided by Agfa
Company, Eastman Kodak Company, Fuji Photo Film Company, and Konica
Corporation. These data were then used to estimate the CIELAB colour gamut that
each paper and film dye set could produce. This estimate was achieved by
mathematical modeling (by several of the participating companies) using methods
which were different but gave very similar results. Annex A provides additional
reference material concerning the method used in selecting aim values.
The following documents provide reference information on the computational
methods used in gamut determination:
1. N. Ohta, “The Color Gamut Obtainable by the Combination of Subtractive Color
Dyes. V. Optimum Absorption Bands as Defined by Nonlinear Optimization
Technique.” Journal of Imaging Science, 30[ 11, 9- 12( 1986).
M. Inui, “Fast Algorithm for Computing Color Gamuts,” Color Research and
2.
Application, 18[5], 341-348 (1993).
All computations were based upon the use of the CIE 2 degree observer and D,,
illuminant. All transmission measurements were made using diffuse/normal or
normal/diffuse geometry as defined for total transmittance. All reflection
measurements were made using 0”/45 O or 45 O/O” geometry as defined in IS0
13655. The reference white was assumed to be a perfect diffuser. The use of an
absolute reference allows all colours on similar media (reflection or transmission)
that have the same calorimetric definition to also look the same when viewed at the
same time.
The gamut plots developed were then used to determine the colour gamuts for film
and paper that were common to all of the provided dye families. The limiting values
of chroma were then reduced to 80% of their computed values to create a “common
gamut” for purposes of target design.
The goal was to have all coloured patches defined in the same way (regardless of the
product used) and to have as many patches as practical. The defined colour gamut
therefore required a pattern with a consistent reference. An existing colour input
target provided by Eastman Kodak Company under the designation of “Kodak
Colour Reproduction Guides, Q-6O’rM” was used as a guide in the development of the
target. The Q-60 TM target used 12 approximately uniformly spaced hue angles in
CIELAB. These were sampled at three chroma values at each of three lightness
levels. Although this pattern does not provide equal spacing in terms of AEZ,,, it
does provide an easily understandable and defined patch arrangement. It was
adopted for these targets with the addition of a fourth product-specific chroma value
at each hue angle/lightness combination.
Lightness levels were chosen for each hue angle to best characterize the gamut at that
hue angle. The three common chroma values were then chosen such that one fell on
the computed 80% chroma limit common to all the products and the others were
equally spaced in chroma between this value and the neutral. The fourth chroma,
which is product-specific, was defined to be the maximum available from each
product at the specific hue angle and lightness level. This provided a consistent
mapping for all products.
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IS0 12641:1997(E) 0 IS0
It was also felt to be important to include scales in each of the individual dyes, dye
pairs, and a dye neutral areas to define product minimum and maximum
along with
densi ties.
A “vendor-optional” area was provided so that different target manufacturers could
add unique patches of their own determination beyond those which are required by
this International Standard.
Manufacturing tolerances
In order to permit practical production of these targets, tolerances had to be set
which were capable of being achieved over a significant number of targets.
However, this conflicted with the relatively narrow tolerances required for numerical
colour calibration. Different tolerances were therefore defined for differing
applications, with the objective of minimizing variations as far as was reasonable.
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IS0 12641:1997(E)
INTERNATIONAL STANDARD @ IS0
Graphic technology - Prepress digital data exchange - Colour targets
for input scanner calibration
3 Definitions
1 Scope
This International Standard defines the layout and For the purposes of this International Standard, the
calorimetric values of targets for use in the calibration of a following definitions apply.
photographic product/input scanner combination (as used in
the preparatory process for printing and publishing). One 3.1 CIE tristimulus values: Amounts of the three reference
target is defined for positive colour transparency film and colour stimuli, in the CIE-specified trichromatic system,
another is defined for colour photographic paper. required to match the colour of the stimulus considered.
NOTE 1 In the 193 1 CIE standard calorimetric system, the
tristimulus values are represented by the symbols X, Y, 2.
2 Normative references
3.2 CIELAB colour difference; CIE 1976 L*, a*, b*
The following standards contain provisions which, through
colour difference, AEZ,: Difference between two colour
reference in this text, constitute provisions of this
stimuli defined as the Euclidean distance between the points
International Standard. At the time of publication, the
representing them in L*, a*, b* space. [International
editions indicated were valid. All standards are subject to
Lighting Vocabulary 845-03-551.
revision, and parties to agreements based on this
International Standard are encouraged to investigate the
AE z. = [ ( AL*)2 + ( Aa*) + ( Ab*)2 ] ‘/z
possibility of applying the most recent editions of the
standards indicated below. Members of IEC and IS0
where
maintain registers of currently valid International Standards.
AL*, Aa* and Ab* refer to the difference between
corresponding values for the two stimuli.
ISO/IEC 646: 199 1, Information technology - IS0 7-bit
coded character set for information interchange.
3.3 CIELAB colour space: CIE 1976 L* a* b* colour
space: Three-dimensional, approximately uniform, colour
IS0 1008: 1992, Photography - Paper dimensions -
space produced by plotting in rectangular coordinates the
Pictorial sheets.
quantities L*, a* and b* defined by the equations:
IS0 10 12: 199 1, Photography - Film dimensions -
L* = 116[f(YlY#.,)] - 16
Pictorial sheets .
a* = SOO[f(XlX,,) - f(Y/Y,,)]
b* = 2OO[f(YIY,,) - f(Z/Zn)]
IS0 13655: 1996, Graphic technology - Spectral
measurement and calorimetric computation for graphic
where for:
arts images.
X/X,, > 0,008 856, f(XlX,,) = (XIX,)‘”
Y/Y,, > 0,008 856, f( Y/q,) = (Y/Y,,)“’
CIE 15.2: 1986, Colorimetry (second edition).
Z/Z,, > 0,008 856, f(Z/Z,,) = (ZlZ,,)“3
CIE 17.4: 1987, International Lighting Vocabulary (fourth
and for:
edition).
XIX,, I 0,008 856, f(X/X,,) = 7,786 7(X/X,,)+16/116
7( Y/Y,,)+1 6/l 16
r/Y,, I 0,008 856, f( Y/Y,,) = 7,786
7(Z/Z,,)+16/116
Z/z,, I 0,008 856, f(Z/Z,,) = 7,786
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@ IS0
IS0 12641:1997(E)
confused with minimum neutral density.
and X,,
= 96,422,
= 100,000 and
K,
3.14 minimum neutral density: Minimum density that a
= 82,521, for the conditions of IS0 13655.
zn
photographic product can achieve (maximum transmittance
or reflectance factors) and maintain a C,*, = 0.
Further:
Czb = (a*’ + b*2)s
NOTE 3 It should not be confused with minimum density
(Dmin).
and
h ab = tan“(b*la*)
3.15 maximum density (Dmax): Density corresponding
to the minimum transmittance or reflectance factor that a
where:
photographic product can achieve.
if a*>0
0” < h,, < 90”
b* 2 0
NOTE 4 It is not necessarily neutral in colour and should not be
90” < 180” if a* 5 0
s huh
confused with maximum neutral density.
b*>O
a*<0
180” I h, < 270” if
3.16 maximum neutral density: Density corresponding to
b* I 0
the maximum density that a photographic product can
270” I h,, < 360” if a* 2 0
achieve (minimum transmittance or reflectance factors) and
b*
maintain a C,*,) = 0,
[CIE Publication 15.21
NOTE 5 It should not be confused with maximum density
3.4 transmittance factor: Ratio of the measured flux
(Dmax).
transmitted by the sample material to the measured flux
when the sample material is removed from the sampling
3.17 input scanner: Device capable of converting the light
aperture of the measuring device.
reflectance or transmittance of a photographic (or other
hardcopy) sample into an electronic signal, where the
3.5 transmission density: Logarithm to base ten of the
electronic signal is arranged to have an organized
reciprocal of the transmittance factor.
relationship to the spatial areas of the image evaluated.
3.6 reflectance factor: Ratio of the measured flux
3.18 product-specific target areas: Portions of the test
reflected from the sample material to the flux reflected from
target whose requirements are specifically defined, but
a perfect reflecting diffuser.
whose values are a function of the particular product used to
make the target.
3.7 reflection density: Logarithm to base ten of the
reciprocal of the reflectance.
3.19 vendor-optional target areas: Portions of the test
target whose content is not specified but is available for use
3.8 colour gamut: Subset of percei .vable colours
by the manufacturer of the target.
reproducible by a device or medium
4 Requirements
3.9 dye set: Combination of light absorbing dyes (usually
referred to as cyan, magenta, and yellow) used in a
All calorimetry referenced within this International
particular photographic product which produce object
Standard shall be based on D,, illuminant, CIE 193 1
colours by the selective subtraction of the incident light.
Standard Calorimetric Observer (2 degree observer) as
defined in CIE 15.2, and computational procedures further
dye scale: Array of physi having varying
3.10 cal areas
defined in 4.5. The reference white is the D,,, illuminant.
nts of one or more (cyan, or yell ow) dyes.
amou magenta,
4.1 Target design
3.11 neutral scale: Array of physical areas having
combination of dye amounts such that their chroma is equal
The target is designed with 5 distinct sections. These are:
to, or near, zero.
1) sampled colour area
2) colour dye scales
3.12 metameric colour stimuli: Spectrally different colour
3) neutral dye scale
stimuli having the same tristimulus values. [International
4) Dmin/Dmax area
Lighting Vocabulary 845-03-051
5) vendor-optional area
3.13 minimum density (Dmin): Density corresponding to
4.2 Transmission targets
the maximum transmittance factor (film) or reflectance
factor (paper) that a photographic product can achieve.
4.2.1 Target layout and physical characteristics
NOTE 2 It is not necessarily neutral in colour and should not be
2
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IS0 12641 :1997(E)
4.2.1.1 Type 1,4 in x 5 in film The layout of the Type 1
approximately neutral and shall have a lightness (L*) of
colour transmission input calibration target as viewed from
approximately 50. The non-image area shall extend at least
the support side of the film shall be as shown in figure 1.
4,5 mm beyond the row and column borders on the top and
This layout is intended for use with film material having a
sides and at least 10 mm on the bottom to provide for
size of 4 in x 5 in (lo,2 cm x 12,7 cm) in accordance with
identification information.
IS0 1012. All non-image areas of the target shall be
IS0 12641 :I 997 Product Name
199732
Figure 1 - Layout, Type 1 colour transmission target
6 7 8 9 10 11 1
I
,
IS0 12641 :1997 Product Name
d997:12
Figure 2 - Type 1 target, row and column numbering
3
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@ IS0
IS0 12641:1997(E)
requirements are identical to those of this International Standard.
Target row and column numbering shall be of high density
and as shown in figure 2. Vertical lines may be used to
4.2.1.2 Type 2,35 mm film The Type 2 layout of the
separate columns 12 and 13; 15, 16, and 17; 19 and 20.
colour transmission input calibration target, as viewed from
Indicators may be used at the intersection of target patches.
the support side of the product, shall be as shown in figure 4
These may be points, crosses, or other symbols, and may be
(frames 35-1 through 35-7). This layout is intended for use
of any density or colour desired. If used, they shall be less
on film material having a basic format of 35 mm. This
than 0,3 mm in width. No other marking lines shall be
layout may be provided either as a single strip of film or as
included within the body of the Al through L19 portion of
seven mounted 35 mm transparencies.
the target.
The target shall be divided as follows:
area from the
Lines shall be included to separate the Dmin
first step and the Dmax areafrom the last step of the 22-step
Frame 35-l The Dmin, neutral scale, and Dmax patches
neutral scale along the bottom of the target.
from the bottom of the Type 1 target format
Frame 35-2 Columns 1 through 4 of the Type 1 target
Unless otherwise noted, all lines shall be neutral and have a
format
lightness (L*) no greater than that specified for background.
5 through 8 of the Type 1 target
Frame 35-3 Columns
format
Fiducial marks shall be included in each corner of the main
Columns 9 through 12 of the Type 1 target
Frame 35-4
body of the target as shown in figure 3. These shall be
format
arranged such that they “point” towards the inside or centre
target
Frame 35-5 Columns 13 through 16 of the Type 1
of the target.
format
Columns 17 through 19 of the Type 1 target
Frame 35-6
Because target patches are 4,s mm x 4,5 mm in size (see
format
4.2.2), the intersection of the lines of the fiducial marks
Frame 35-7 Columns 20 through 22 of the Type 1 target
shall be offset 45 mm in both the horizontal and vertical
format
direction from the centre of the nearest patch to provide a
reference for automatic measurement alignment.
In addition each frame shall have a s ix step neutral scale as
column N with L* values as follows:
Fiducial marks shall be clear lines on the neutral
background and shall be approximately 0,l mm in width.
(top)
Step 1 82
Step 2 66
Step 3 50
Step 4 34
Step5 18
Step 6 2
All non-image areas of the target shall be approximately
*
neutral and shall have a lightness of approximately 50.
CL >
Each frame of contain the following
the target shall
information in English text:
a) IS0 12641:1997;
b) A frame number of the form 35-X;
c) The name of the film product or product family;
The year and month of production of the target in
d)
Figure 3 - Fiducial mark design
the form yyyy:mm.
The area at the bottom of the target shall contain the
NOTE 7 Targets bearing the designation IT8.7/1- 1993 are
following information in English text:
prepared in accordance with ANSI IT8.7/1-1993 whose technical
requirements are identical to those of this International Standard.
a> IS0 12641:1997;
The name of the film product or product family;
b)
this
If provided as individually mounted transparencies,
The year and month of production of the target
C>
same information shall be repeated on the mount.
in the form yyyymm; and
d) An area of at least 10 mm x 25 mm for addition
and reference lines shall be high in
The frame numbering
of a unique identification.
density and as shown in figure 5.
NOTE 6 Targets bearing the designation IT8.7/1-1993 are
prepared in accordance with ANSI IT8.7/1-1993 whose technical
4
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IS0 12641 :1997(E)
1234567N
12341234N
G
H
B
C I
8
D J
E K
16 A~
L
F
Frame 35-1 Frame 35-2
56785678N 9 10 11 12 9 10 11 12 N
G G
H
B B H
C C I
I 1
J
D D J
K
K
E E
*4
A~
L
L
F F
Frame 35-3
Frame 35-4
13 14 15 16 13 14 15 16 N 17 18 19 17 18 19 N
G
A G
H H
B B
I C I
C
D J D J
K K
E E
L
L
F F
*E
Frame 35-5 Frame 35-6
I
20 21 22 20 21
22 N
.
G
A
H
B
I
C
J
D
K
E
L
F
.
I
Frame 35-7
Figure 4 - Layout, Type 2 colour transmission target
5
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@ IS0
2641: 1997(E)
1 2 3 4 1 2 3 4 N
4
A G
H
B
C I
D J
E K
F L
-
IS0 12641 :I 997 Product Name
1997:12
Type 2 target, row and column numbering
Figure 5 -
4.2.3 Colour gamut mapping
Divider lines shall be included in Frame 35-l between
Dmin and step 1 of the neutral scale, and step 22 of the
neutral scale and Dmax. The hue angle, lightness, and chroma of the target patches
contained in the sampled colour area portion of the target,
Unless otherwise noted, all lines shall be neutral and have a Rows A through L and Columns 1 through 12, shall be in
lightness (L*) no greater than that specified for background. accordance with table 1 under the measurement conditions
of 4.5.
4.2.1.3 Type 3,35 mm film version of Type 1 target
(optional) A 35 mm version of the Type 1 target may be Where a product is not capable of achieving specific
provided at the discretion of the film vendor. If provided, it chroma values indicated in this specification, the patch
corresponding to that value shall be exposed as a
shall contain labeling information to ensure that scanned
data from the 35 mm version of the target cannot be background neutral as defined in 4.2.1.1. In all cases,
confused with scanned data from the full size version of the patches in columns 4, 8 and 12, as shown in table 1, shall
be included.
target. This target shall be a reduced size version of the
Type 1 target, but shall not be required to meet the
4.2.4 Neutral and dye scale values
calorimetric requirements of this specification. Colours
achieved will be the best efforts of the manufacturer.
The specific values of patches Al 3 through L 19 shall be
NOTE 8 See annex B for recommendations on use of this format defined by the manufacturer of the film used to create a
of the test target.
specific target. The batch mean (for uncalibrated targets) or
measured CIE X Y 2 and L* C& /z& values (for calibrated
targets) of these patches shall be reported by the
4.2.2 Patch size
manufacturer in accordance with 4.6.
The transmission targets shall be made with patch
The criteria by which the aim values for these patches shall
dimensions as follows:
be determined (under the measurement conditions of 4.5)
4,5 mm x 4,5 mm
Type 1 are as follows:
3,2 mm x 3,2 mm
Type 2
Patch Al6 shall be the minimum neutral density ( Cz,, = 0)
The Dmin area, the 22-step neutral scale, and the Dmax
that the product can normally achieve.
area shall be two patches high.
Patch L16 shall be the maximum neutral density ( C$, = 0)
that the product can normally achieve.
Patches B 16 through K16 shall be equally spaced in L*
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@ IS0
IS0 12641 :1997(E)
Table 1 - Hue angle, lightness and chroma for transmission target
R
0 Hue
Ll Cl c2 c3 c4 L2 Cl c2 c3 c4 L3 Cl c2 c3 c4
W Angle
----------_- .--.--_______--- _____ --------
A 16 15 10 21 31 (1) 35 15 30 45 (1) 60 8 16 24 (1)
B 41 20 11 23 34 (1) 40 17 34 51 (1) 65 7 15 22 (1)
C 67 30 11 22 34 (1) 55 20 40 60 (1) 70 9 17 26 (1)
D 92 25 9 18 27 (1) 50 17 35 52 (1) 75 23 46 69 (1)
E 119 30 11 22 33 (1) 60 20 39 59 (1) 75 12 25 37 (1)
F 161 25 10 21 31 (1) 45 17 35 52 (1) 65 12 25 37 (1)
G 190 20 7 14 21 (1) 45 14 29 43 (1) 65 11 23 34 (1)
H 229 20 7 15 22 (1) 40 13 25 38 (1) 65 7 15 22 (1)
I 274 25 14 27 41 (1) 45 10 21 31 (1) 65 6 12 17 (1)
J 299 10 17 34 51 (1) 35 13 27 40 (1) 60 7 14 21 (1)
K 325 15 13 26 39 (1) 30 17 35 52 (1) 55 12 23 35 (1)
L 350 15 10 21 31 (1) 30 16 33 49 (1) 55 10 21 31 (1)
Column 1 2 3 4 5 6 7 8 9 10 11 12
(1) - These values are specific to the product used to create the target and equal to maximum Cg, available
at the hue angle and L* specified. They are to be defined by the manufacturer of the product used to make
the target.
between the L* values of patches Al6 and L16. measurement conditions of 4.5, reading from left to right
across the target. Cz,, aim values shall be 0.
Patches Al 3 through L13 shall contain the same amounts of
cyan dye as used to create the neutral patches of Al6
Step 1 82 Step 2 78
through L 16.
Step 3 74 Step 4 70
Step 5
66 Step 6 62
Patches Al4 through L14 shall contain the same amounts of Step 7 58 Step 8 54
magenta dye as used to create the neutral patches of Al6 Step 9 50 Step 10 46
through L 16.
Step 11 42 Step 12 38
Step 13
34 Step 14 30
Patches A15 through L15 shall contain the same amounts of Step 15 26 Step 16 22
yellow dye as used to create the neutral patches of Al 6 Step 17 18 Step 18 14
through L16.
Step 19 10 Step 20 6
Step 21 4 Step 22 2
Patches Al7 through L17 shall contain the same amounts of
magenta and yellow dye (will appear red) as used to create The patch located to the left of Step 1 of the grey scale
the neutral patches of Al6 through L16. (column 0) shall be at the Dmin of the product. The patch to
the right of Step 22 (column 23) of the grey scale shall be at
Patches Al 8 through L18 shall contain the same amounts of product Dmax.
cyan and yellow dye (will appear green) as used to create
the neutral patches of Al6 through L16.
4.3 Reflection targets
Patches A19 through L19 shall contain the same amounts of
4.3.1 Target layout and physical characteristics
cyan and magenta dye (will appear blue) as used to create
the neutral patches of Al6 through L16.
The layout of the colour reflection input calibration target
shall be as shown in figure 6. This layout is intended for
NOTE 9 It is recognized that it will be difficult to achieve these
use on material having a basic format of 5 in x 7 in (12,7
aim dye amounts, particularly in patches of high density, because
cm x 17,8 cm) in accordance with IS0 1008.
of overlapping spectral sensitivities. Manufacturers are expected
to achieve these goals to the extent possible.
All non-image areas of the target shall be approximately
neutral and shall have a lightness (L*) of approximately 50.
4.2.5 Neutral scale mapping
The non-image area shall extend at least 4,5 mm beyond the
row and column borders on the top and sides and at least 10
The neutral scale lying along the bottom of the target shall
mm on the bottom to provide for identification information.
have the following L* aim values, based on the
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IS0 12641:1997(E)
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
I
A
A
BIIIIII~~ I I I 1 I I I I I I I I I I
4
I
I I I I I I I I I I I I i I I I I I I I I ll
L - I
I
I
J
J
K K
L L
1 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 20 21 r
19 2.2
/
IS0 12641 :1997 Product Name
199732
Layout, colour reflection target
Figure 6 -
J 1 2
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 L
A
A
B
B
C C
D
D
E
E
F F
G G
H H
I I
J J
K K
L L
l 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
17 18 19 20 21 22 i-
IS0 12641: 1997 Product Name
1997:12
Figure 7 - Reflection target, row and column numbering
than 0,3 mm in width. No other marking lines shall be
Target row and column numbering shall be of high density
included within the bo
...
SLOVENSKI STANDARD
SIST ISO 12641:2002
01-november-2002
*UDILþQDWHKQRORJLMD,]PHQMDYDGLJLWDOQLKSRGDWNRYYJUDILþQLSULSUDYL%DUYQH
WDEOLFH]DXPHUMDQMHVNHQHUMHY
Graphic technology -- Prepress digital data exchange -- Colour targets for input scanner
calibration
Technologie graphique -- Échange de données numériques de préimpression -- Cibles
de couleur pour étalonnage à l'entrée du scanner
Ta slovenski standard je istoveten z: ISO 12641:1997
ICS:
35.240.30 Uporabniške rešitve IT v IT applications in information,
informatiki, dokumentiranju in documentation and
založništvu publishing
37.080 Uporabniške rešitve za Document imaging
predstavitev dokumentov applications
37.100.99 'UXJLVWDQGDUGLY]YH]L] Other standards related to
JUDILþQRWHKQRORJLMR graphic technology
SIST ISO 12641:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ISO 12641:2002
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SIST ISO 12641:2002
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SIST ISO 12641:2002
IS0 12641:1997(E)
Contents
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
1
1 Scope .
......................................... 1
2 Normative references
................................................. 1
3 Definitions
2
...............................................
4 Requirements
2
4.1 Targetdesign .
......................................... 3
4.2 Transmission targets
7
............................................
4.3 Reflection targets
10
...........................
4.4 Allowable tolerances on patch values
................ 11
4.5 Spectral measurement and calorimetric calculation
............................................. 11
4.6 Data reporting
11
............................................
4.7 Datafileformat
.......................................... 12
4.8 Useable target life
Annexes
....................... 13
A Gamut mapping - computational reference
........................................... 14
B Application notes
............................................ 17
C Data file format
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 CH-1211 Geneve 20 l Switzerland
Internet central @ iso.ch
x.400 c=ch; a=40Onet; p=iso; o=isocs; s=central
Printed in Switzerland
ii
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SIST ISO 12641:2002
@ IS0
lSO12641:1997( E)
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 12641 was prepared by Technical Committee
ISO/TC 130, Graphic technology.
Annexes A, B, and C of this International Standard are for information only.
0.”
Ill
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SIST ISO 12641:2002
IS0 12641 :1997(E) @ IS0
Introduction
The technical requirements of this International Standard are identical to the
American National Standards IT8.7/1- 1993 and IT8.7/2- 1993. These documents
resulted from the joint efforts of an international industry group that included
participants representing a broad range of prepress vendors, film manufacturers, and
users. This group, initially identified as the DDES (Digital Data Exchange
Standards) Committee, later became the founders of the ANSI IT8 (Image
Technology) accredited standards committee which is responsible for electronic data
exchange standards in graphic arts prepress.
Purpose of this International Standard
Colour input scanners do not all analyze colour the same way the human eye does.
These devices are designed to optimize the signal generated when typical materials
are scanned. Colour reflection and transparency products use various combinations
of proprietary dye sets to achieve visual responses that simulate the colour appea-
rance of natural scene elements. The ability to achieve the same colour appearance
from different combinations of dyes is referred to as metamerism. Because both
photographic dyes and input scanner sensitivities vary from product to product, there
is a variability in the input scanner response to metameric colours produced by the
various materials. The intent of this International Standard is to define an input test
target that will allow any colour input scanner to be calibrated with any film or paper
dye set used to create the target. This International Standard is intended to address
the colour reflection and transparency products which are generally used for input to
the preparatory process for printing and publishing.
The target was designed to be useable for calibration by visual comparison and as a
numerical data target for electronic systems and future development. The target
design made use of a uniform colour space to optimize the spacing of target patches.
The tolerances developed for individual coloured patches meet the values needed for
both numerical and visual analysis.
Design of the target
The CIE 1976 (L*a*b*) or CIELAB colour space was chosen as the space to be used
for the design of the colour calibration target. Uniform spacing in hue angle,
lightness and chroma, and tolerancing in terms of differences in these parameters
(AEzb) is believed to provide a reasonable distribution of coloured patches in the
most effective manner. Although CIELAB was defined with reference to reflection
viewing conditions, tolerancing in terms of vector differences (AE,*& does provide a
reasonable error estimate for transmission materials as well, although the uniformity
of the space is dependent upon the conditions of viewing.
The design goal was to define a target that would have, as its main part, as many
common coloured patches as was practical, regardless of the dye set used. It was
iv
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SIST ISO 12641:2002
0 IS0
IS0 12641:1997(E)
determined that the remainder of the target should define the unique colour
characteristics of the particular dye set used to create a specific target; the values for
each target patch should be established using a common procedure.
To provide a reasonable measure of the colour gamut that is within the capability of
modern colour papers and films, all manufacturers of these products were invited to
provide colour dye data along with the necessary minimum and maximum density
data for each of their image forming colour dye sets. Data were provided by Agfa
Company, Eastman Kodak Company, Fuji Photo Film Company, and Konica
Corporation. These data were then used to estimate the CIELAB colour gamut that
each paper and film dye set could produce. This estimate was achieved by
mathematical modeling (by several of the participating companies) using methods
which were different but gave very similar results. Annex A provides additional
reference material concerning the method used in selecting aim values.
The following documents provide reference information on the computational
methods used in gamut determination:
1. N. Ohta, “The Color Gamut Obtainable by the Combination of Subtractive Color
Dyes. V. Optimum Absorption Bands as Defined by Nonlinear Optimization
Technique.” Journal of Imaging Science, 30[ 11, 9- 12( 1986).
M. Inui, “Fast Algorithm for Computing Color Gamuts,” Color Research and
2.
Application, 18[5], 341-348 (1993).
All computations were based upon the use of the CIE 2 degree observer and D,,
illuminant. All transmission measurements were made using diffuse/normal or
normal/diffuse geometry as defined for total transmittance. All reflection
measurements were made using 0”/45 O or 45 O/O” geometry as defined in IS0
13655. The reference white was assumed to be a perfect diffuser. The use of an
absolute reference allows all colours on similar media (reflection or transmission)
that have the same calorimetric definition to also look the same when viewed at the
same time.
The gamut plots developed were then used to determine the colour gamuts for film
and paper that were common to all of the provided dye families. The limiting values
of chroma were then reduced to 80% of their computed values to create a “common
gamut” for purposes of target design.
The goal was to have all coloured patches defined in the same way (regardless of the
product used) and to have as many patches as practical. The defined colour gamut
therefore required a pattern with a consistent reference. An existing colour input
target provided by Eastman Kodak Company under the designation of “Kodak
Colour Reproduction Guides, Q-6O’rM” was used as a guide in the development of the
target. The Q-60 TM target used 12 approximately uniformly spaced hue angles in
CIELAB. These were sampled at three chroma values at each of three lightness
levels. Although this pattern does not provide equal spacing in terms of AEZ,,, it
does provide an easily understandable and defined patch arrangement. It was
adopted for these targets with the addition of a fourth product-specific chroma value
at each hue angle/lightness combination.
Lightness levels were chosen for each hue angle to best characterize the gamut at that
hue angle. The three common chroma values were then chosen such that one fell on
the computed 80% chroma limit common to all the products and the others were
equally spaced in chroma between this value and the neutral. The fourth chroma,
which is product-specific, was defined to be the maximum available from each
product at the specific hue angle and lightness level. This provided a consistent
mapping for all products.
---------------------- Page: 7 ----------------------
SIST ISO 12641:2002
IS0 12641:1997(E) 0 IS0
It was also felt to be important to include scales in each of the individual dyes, dye
pairs, and a dye neutral areas to define product minimum and maximum
along with
densi ties.
A “vendor-optional” area was provided so that different target manufacturers could
add unique patches of their own determination beyond those which are required by
this International Standard.
Manufacturing tolerances
In order to permit practical production of these targets, tolerances had to be set
which were capable of being achieved over a significant number of targets.
However, this conflicted with the relatively narrow tolerances required for numerical
colour calibration. Different tolerances were therefore defined for differing
applications, with the objective of minimizing variations as far as was reasonable.
vi
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SIST ISO 12641:2002
IS0 12641:1997(E)
INTERNATIONAL STANDARD @ IS0
Graphic technology - Prepress digital data exchange - Colour targets
for input scanner calibration
3 Definitions
1 Scope
This International Standard defines the layout and For the purposes of this International Standard, the
calorimetric values of targets for use in the calibration of a following definitions apply.
photographic product/input scanner combination (as used in
the preparatory process for printing and publishing). One 3.1 CIE tristimulus values: Amounts of the three reference
target is defined for positive colour transparency film and colour stimuli, in the CIE-specified trichromatic system,
another is defined for colour photographic paper. required to match the colour of the stimulus considered.
NOTE 1 In the 193 1 CIE standard calorimetric system, the
tristimulus values are represented by the symbols X, Y, 2.
2 Normative references
3.2 CIELAB colour difference; CIE 1976 L*, a*, b*
The following standards contain provisions which, through
colour difference, AEZ,: Difference between two colour
reference in this text, constitute provisions of this
stimuli defined as the Euclidean distance between the points
International Standard. At the time of publication, the
representing them in L*, a*, b* space. [International
editions indicated were valid. All standards are subject to
Lighting Vocabulary 845-03-551.
revision, and parties to agreements based on this
International Standard are encouraged to investigate the
AE z. = [ ( AL*)2 + ( Aa*) + ( Ab*)2 ] ‘/z
possibility of applying the most recent editions of the
standards indicated below. Members of IEC and IS0
where
maintain registers of currently valid International Standards.
AL*, Aa* and Ab* refer to the difference between
corresponding values for the two stimuli.
ISO/IEC 646: 199 1, Information technology - IS0 7-bit
coded character set for information interchange.
3.3 CIELAB colour space: CIE 1976 L* a* b* colour
space: Three-dimensional, approximately uniform, colour
IS0 1008: 1992, Photography - Paper dimensions -
space produced by plotting in rectangular coordinates the
Pictorial sheets.
quantities L*, a* and b* defined by the equations:
IS0 10 12: 199 1, Photography - Film dimensions -
L* = 116[f(YlY#.,)] - 16
Pictorial sheets .
a* = SOO[f(XlX,,) - f(Y/Y,,)]
b* = 2OO[f(YIY,,) - f(Z/Zn)]
IS0 13655: 1996, Graphic technology - Spectral
measurement and calorimetric computation for graphic
where for:
arts images.
X/X,, > 0,008 856, f(XlX,,) = (XIX,)‘”
Y/Y,, > 0,008 856, f( Y/q,) = (Y/Y,,)“’
CIE 15.2: 1986, Colorimetry (second edition).
Z/Z,, > 0,008 856, f(Z/Z,,) = (ZlZ,,)“3
CIE 17.4: 1987, International Lighting Vocabulary (fourth
and for:
edition).
XIX,, I 0,008 856, f(X/X,,) = 7,786 7(X/X,,)+16/116
7( Y/Y,,)+1 6/l 16
r/Y,, I 0,008 856, f( Y/Y,,) = 7,786
7(Z/Z,,)+16/116
Z/z,, I 0,008 856, f(Z/Z,,) = 7,786
---------------------- Page: 9 ----------------------
SIST ISO 12641:2002
@ IS0
IS0 12641:1997(E)
confused with minimum neutral density.
and X,,
= 96,422,
= 100,000 and
K,
3.14 minimum neutral density: Minimum density that a
= 82,521, for the conditions of IS0 13655.
zn
photographic product can achieve (maximum transmittance
or reflectance factors) and maintain a C,*, = 0.
Further:
Czb = (a*’ + b*2)s
NOTE 3 It should not be confused with minimum density
(Dmin).
and
h ab = tan“(b*la*)
3.15 maximum density (Dmax): Density corresponding
to the minimum transmittance or reflectance factor that a
where:
photographic product can achieve.
if a*>0
0” < h,, < 90”
b* 2 0
NOTE 4 It is not necessarily neutral in colour and should not be
90” < 180” if a* 5 0
s huh
confused with maximum neutral density.
b*>O
a*<0
180” I h, < 270” if
3.16 maximum neutral density: Density corresponding to
b* I 0
the maximum density that a photographic product can
270” I h,, < 360” if a* 2 0
achieve (minimum transmittance or reflectance factors) and
b*
maintain a C,*,) = 0,
[CIE Publication 15.21
NOTE 5 It should not be confused with maximum density
3.4 transmittance factor: Ratio of the measured flux
(Dmax).
transmitted by the sample material to the measured flux
when the sample material is removed from the sampling
3.17 input scanner: Device capable of converting the light
aperture of the measuring device.
reflectance or transmittance of a photographic (or other
hardcopy) sample into an electronic signal, where the
3.5 transmission density: Logarithm to base ten of the
electronic signal is arranged to have an organized
reciprocal of the transmittance factor.
relationship to the spatial areas of the image evaluated.
3.6 reflectance factor: Ratio of the measured flux
3.18 product-specific target areas: Portions of the test
reflected from the sample material to the flux reflected from
target whose requirements are specifically defined, but
a perfect reflecting diffuser.
whose values are a function of the particular product used to
make the target.
3.7 reflection density: Logarithm to base ten of the
reciprocal of the reflectance.
3.19 vendor-optional target areas: Portions of the test
target whose content is not specified but is available for use
3.8 colour gamut: Subset of percei .vable colours
by the manufacturer of the target.
reproducible by a device or medium
4 Requirements
3.9 dye set: Combination of light absorbing dyes (usually
referred to as cyan, magenta, and yellow) used in a
All calorimetry referenced within this International
particular photographic product which produce object
Standard shall be based on D,, illuminant, CIE 193 1
colours by the selective subtraction of the incident light.
Standard Calorimetric Observer (2 degree observer) as
defined in CIE 15.2, and computational procedures further
dye scale: Array of physi having varying
3.10 cal areas
defined in 4.5. The reference white is the D,,, illuminant.
nts of one or more (cyan, or yell ow) dyes.
amou magenta,
4.1 Target design
3.11 neutral scale: Array of physical areas having
combination of dye amounts such that their chroma is equal
The target is designed with 5 distinct sections. These are:
to, or near, zero.
1) sampled colour area
2) colour dye scales
3.12 metameric colour stimuli: Spectrally different colour
3) neutral dye scale
stimuli having the same tristimulus values. [International
4) Dmin/Dmax area
Lighting Vocabulary 845-03-051
5) vendor-optional area
3.13 minimum density (Dmin): Density corresponding to
4.2 Transmission targets
the maximum transmittance factor (film) or reflectance
factor (paper) that a photographic product can achieve.
4.2.1 Target layout and physical characteristics
NOTE 2 It is not necessarily neutral in colour and should not be
2
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SIST ISO 12641:2002
@ IS0
IS0 12641 :1997(E)
4.2.1.1 Type 1,4 in x 5 in film The layout of the Type 1
approximately neutral and shall have a lightness (L*) of
colour transmission input calibration target as viewed from
approximately 50. The non-image area shall extend at least
the support side of the film shall be as shown in figure 1.
4,5 mm beyond the row and column borders on the top and
This layout is intended for use with film material having a
sides and at least 10 mm on the bottom to provide for
size of 4 in x 5 in (lo,2 cm x 12,7 cm) in accordance with
identification information.
IS0 1012. All non-image areas of the target shall be
IS0 12641 :I 997 Product Name
199732
Figure 1 - Layout, Type 1 colour transmission target
6 7 8 9 10 11 1
I
,
IS0 12641 :1997 Product Name
d997:12
Figure 2 - Type 1 target, row and column numbering
3
---------------------- Page: 11 ----------------------
SIST ISO 12641:2002
@ IS0
IS0 12641:1997(E)
requirements are identical to those of this International Standard.
Target row and column numbering shall be of high density
and as shown in figure 2. Vertical lines may be used to
4.2.1.2 Type 2,35 mm film The Type 2 layout of the
separate columns 12 and 13; 15, 16, and 17; 19 and 20.
colour transmission input calibration target, as viewed from
Indicators may be used at the intersection of target patches.
the support side of the product, shall be as shown in figure 4
These may be points, crosses, or other symbols, and may be
(frames 35-1 through 35-7). This layout is intended for use
of any density or colour desired. If used, they shall be less
on film material having a basic format of 35 mm. This
than 0,3 mm in width. No other marking lines shall be
layout may be provided either as a single strip of film or as
included within the body of the Al through L19 portion of
seven mounted 35 mm transparencies.
the target.
The target shall be divided as follows:
area from the
Lines shall be included to separate the Dmin
first step and the Dmax areafrom the last step of the 22-step
Frame 35-l The Dmin, neutral scale, and Dmax patches
neutral scale along the bottom of the target.
from the bottom of the Type 1 target format
Frame 35-2 Columns 1 through 4 of the Type 1 target
Unless otherwise noted, all lines shall be neutral and have a
format
lightness (L*) no greater than that specified for background.
5 through 8 of the Type 1 target
Frame 35-3 Columns
format
Fiducial marks shall be included in each corner of the main
Columns 9 through 12 of the Type 1 target
Frame 35-4
body of the target as shown in figure 3. These shall be
format
arranged such that they “point” towards the inside or centre
target
Frame 35-5 Columns 13 through 16 of the Type 1
of the target.
format
Columns 17 through 19 of the Type 1 target
Frame 35-6
Because target patches are 4,s mm x 4,5 mm in size (see
format
4.2.2), the intersection of the lines of the fiducial marks
Frame 35-7 Columns 20 through 22 of the Type 1 target
shall be offset 45 mm in both the horizontal and vertical
format
direction from the centre of the nearest patch to provide a
reference for automatic measurement alignment.
In addition each frame shall have a s ix step neutral scale as
column N with L* values as follows:
Fiducial marks shall be clear lines on the neutral
background and shall be approximately 0,l mm in width.
(top)
Step 1 82
Step 2 66
Step 3 50
Step 4 34
Step5 18
Step 6 2
All non-image areas of the target shall be approximately
*
neutral and shall have a lightness of approximately 50.
CL >
Each frame of contain the following
the target shall
information in English text:
a) IS0 12641:1997;
b) A frame number of the form 35-X;
c) The name of the film product or product family;
The year and month of production of the target in
d)
Figure 3 - Fiducial mark design
the form yyyy:mm.
The area at the bottom of the target shall contain the
NOTE 7 Targets bearing the designation IT8.7/1- 1993 are
following information in English text:
prepared in accordance with ANSI IT8.7/1-1993 whose technical
requirements are identical to those of this International Standard.
a> IS0 12641:1997;
The name of the film product or product family;
b)
this
If provided as individually mounted transparencies,
The year and month of production of the target
C>
same information shall be repeated on the mount.
in the form yyyymm; and
d) An area of at least 10 mm x 25 mm for addition
and reference lines shall be high in
The frame numbering
of a unique identification.
density and as shown in figure 5.
NOTE 6 Targets bearing the designation IT8.7/1-1993 are
prepared in accordance with ANSI IT8.7/1-1993 whose technical
4
---------------------- Page: 12 ----------------------
SIST ISO 12641:2002
@ IS0
IS0 12641 :1997(E)
1234567N
12341234N
G
H
B
C I
8
D J
E K
16 A~
L
F
Frame 35-1 Frame 35-2
56785678N 9 10 11 12 9 10 11 12 N
G G
H
B B H
C C I
I 1
J
D D J
K
K
E E
*4
A~
L
L
F F
Frame 35-3
Frame 35-4
13 14 15 16 13 14 15 16 N 17 18 19 17 18 19 N
G
A G
H H
B B
I C I
C
D J D J
K K
E E
L
L
F F
*E
Frame 35-5 Frame 35-6
I
20 21 22 20 21
22 N
.
G
A
H
B
I
C
J
D
K
E
L
F
.
I
Frame 35-7
Figure 4 - Layout, Type 2 colour transmission target
5
---------------------- Page: 13 ----------------------
SIST ISO 12641:2002
@ IS0
2641: 1997(E)
1 2 3 4 1 2 3 4 N
4
A G
H
B
C I
D J
E K
F L
-
IS0 12641 :I 997 Product Name
1997:12
Type 2 target, row and column numbering
Figure 5 -
4.2.3 Colour gamut mapping
Divider lines shall be included in Frame 35-l between
Dmin and step 1 of the neutral scale, and step 22 of the
neutral scale and Dmax. The hue angle, lightness, and chroma of the target patches
contained in the sampled colour area portion of the target,
Unless otherwise noted, all lines shall be neutral and have a Rows A through L and Columns 1 through 12, shall be in
lightness (L*) no greater than that specified for background. accordance with table 1 under the measurement conditions
of 4.5.
4.2.1.3 Type 3,35 mm film version of Type 1 target
(optional) A 35 mm version of the Type 1 target may be Where a product is not capable of achieving specific
provided at the discretion of the film vendor. If provided, it chroma values indicated in this specification, the patch
corresponding to that value shall be exposed as a
shall contain labeling information to ensure that scanned
data from the 35 mm version of the target cannot be background neutral as defined in 4.2.1.1. In all cases,
confused with scanned data from the full size version of the patches in columns 4, 8 and 12, as shown in table 1, shall
be included.
target. This target shall be a reduced size version of the
Type 1 target, but shall not be required to meet the
4.2.4 Neutral and dye scale values
calorimetric requirements of this specification. Colours
achieved will be the best efforts of the manufacturer.
The specific values of patches Al 3 through L 19 shall be
NOTE 8 See annex B for recommendations on use of this format defined by the manufacturer of the film used to create a
of the test target.
specific target. The batch mean (for uncalibrated targets) or
measured CIE X Y 2 and L* C& /z& values (for calibrated
targets) of these patches shall be reported by the
4.2.2 Patch size
manufacturer in accordance with 4.6.
The transmission targets shall be made with patch
The criteria by which the aim values for these patches shall
dimensions as follows:
be determined (under the measurement conditions of 4.5)
4,5 mm x 4,5 mm
Type 1 are as follows:
3,2 mm x 3,2 mm
Type 2
Patch Al6 shall be the minimum neutral density ( Cz,, = 0)
The Dmin area, the 22-step neutral scale, and the Dmax
that the product can normally achieve.
area shall be two patches high.
Patch L16 shall be the maximum neutral density ( C$, = 0)
that the product can normally achieve.
Patches B 16 through K16 shall be equally spaced in L*
---------------------- Page: 14 ----------------------
SIST ISO 12641:2002
@ IS0
IS0 12641 :1997(E)
Table 1 - Hue angle, lightness and chroma for transmission target
R
0 Hue
Ll Cl c2 c3 c4 L2 Cl c2 c3 c4 L3 Cl c2 c3 c4
W Angle
----------_- .--.--_______--- _____ --------
A 16 15 10 21 31 (1) 35 15 30 45 (1) 60 8 16 24 (1)
B 41 20 11 23 34 (1) 40 17 34 51 (1) 65 7 15 22 (1)
C 67 30 11 22 34 (1) 55 20 40 60 (1) 70 9 17 26 (1)
D 92 25 9 18 27 (1) 50 17 35 52 (1) 75 23 46 69 (1)
E 119 30 11 22 33 (1) 60 20 39 59 (1) 75 12 25 37 (1)
F 161 25 10 21 31 (1) 45 17 35 52 (1) 65 12 25 37 (1)
G 190 20 7 14 21 (1) 45 14 29 43 (1) 65 11 23 34 (1)
H 229 20 7 15 22 (1) 40 13 25 38 (1) 65 7 15 22 (1)
I 274 25 14 27 41 (1) 45 10 21 31 (1) 65 6 12 17 (1)
J 299 10 17 34 51 (1) 35 13 27 40 (1) 60 7 14 21 (1)
K 325 15 13 26 39 (1) 30 17 35 52 (1) 55 12 23 35 (1)
L 350 15 10 21 31 (1) 30 16 33 49 (1) 55 10 21 31 (1)
Column 1 2 3 4 5 6 7 8 9 10 11 12
(1) - These values are specific to the product used to create the target and equal to maximum Cg, available
at the hue angle and L* specified. They are to be defined by the manufacturer of the product used to make
the target.
between the L* values of patches Al6 and L16. measurement conditions of 4.5, reading from left to right
across the target. Cz,, aim values shall be 0.
Patches Al 3 through L13 shall contain the same amounts of
cyan dye as used to create the neutral patches of Al6
Step 1 82 Step 2 78
through L 16.
Step 3 74 Step 4 70
Step 5
66 Step 6 62
Patches Al4 through L14 shall contain the same amounts of Step 7 58 Step 8 54
magenta dye as used to create the neutral patches of Al6 Step 9 50 Step 10 46
through L 16.
Step 11 42 Step 12 38
Step 13
34 Step 14 30
Patches A15 through L15 shall contain the same amounts of Step 15 26 Step 16 22
yellow dye as used to create the neutral patches of Al 6 Step 17 18 Step 18 14
through L16.
Step 19 10 Step 20 6
Step 21 4 Step 22 2
Patches Al7 through L17 shall contain the same amounts of
magenta and yellow dye (will appear red) as used to create The patch located to the left of Step 1 of the grey scale
the neutral patches of Al6 through L16. (column 0) shall be at the Dmin of the product. The patch to
the right of Step 22 (column 23) of the grey scale shall be at
Patches Al 8 through L18 shall contain the same amounts of product Dmax.
cyan and yellow dye (will appear green) as used to create
the neutral patches of Al6 through L16.
4.3 Reflection targets
Patches A19 through L19 shall contain the same amounts of
4.3.1 Target layout and physical characteristics
cyan and magenta dye (will appear blue) as used to create
the neutral patches of Al6 through L16.
The layout of the colour reflection input calibration target
shall be as shown in figure 6. This layout is intended for
NOTE 9 It is recognized that it will be difficult to achieve these
use on material having a basic format of 5 in x 7 in (12,7
aim dye amounts, particularly in patches of high density, because
cm x 17,8 cm) in accord
...
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