SIST EN 61610:1999
(Main)Prints and transparencies produced from electronic sources - Assessment of image quality
Prints and transparencies produced from electronic sources - Assessment of image quality
Applies to the assessment of image attribution on prints and transparencies produced from electronic sources. Specifies test signals, measurement conditions and forms of reporting the results so as to make possible comparison of the results of measurement. Applicable to a wide quality range of colour prints and transparencies.
Beurteilung der Bildqualität von durch elektronischen Quellen erzeugten reflektierenden und transparenten Reproduktionen
Images imprimées et transparents obtenus à partir de sources électroniques - Evaluation de la qualité de l'image
S'applique à l'évaluation des attributs des images produites à partir de sources électroniques sur des imprimés ou des transparents. Spécifie les signaux d'essai, les conditions de mesure et la manière de présenter les résultats dans le but de rendre possible la comparaison de résultat de mesure. S'appliquent à une grande variété de qualité d'imprimées et de transparents en couleur.
Prints and transparencies produced from electronic sources - Assessment of image quality (IEC 61610:1995)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 61610:1999
01-april-1999
Prints and transparencies produced from electronic sources - Assessment of
image quality (IEC 61610:1995)
Prints and transparencies produced from electronic sources - Assessment of image
quality
Beurteilung der Bildqualität von durch elektronischen Quellen erzeugten reflektierenden
und transparenten Reproduktionen
Images imprimées et transparents obtenus à partir de sources électroniques - Evaluation
de la qualité de l'image
Ta slovenski standard je istoveten z: EN 61610:1996
ICS:
35.240.20 Uporabniške rešitve IT pri IT applications in office work
pisarniškem delu
SIST EN 61610:1999 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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NORME CEI
INTERNATIONALE IEC
1610
INTERNATIONAL
Première
édition
STANDARD
First edition
1995-11
Images imprimées et transparents obtenus
à partir des sources électroniques —
Evaluation de la qualité de l'image
Prints and transparencies produced
from electronic sources —
Assessment of image quality
CEI 1995 Droits de reproduction réservés — Copyright — all rights reserved
©
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun pro- any form or by any means, electronic or mechanical,
cédé, électronique ou mécanique, y compris la photocopie et including photocopying and microfilm, without permission
les microfilms, sans l'accord écrit de l'éditeur. in writing from the publisher.
Bureau Central de la Commission Electrotechnique Internationale 3, rue de Varembé Genève, Suisse
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CODE PRIX "
International Electrotechnical Commission
EPRICE COD
IEC MefwiyuapoAHaw 3neKrporexHHVectiaft HOMHCCHA
Pour prix, voir catalogue en vigueur •
•
For price, see current catalogue
---------------------- Page: 2 ----------------------
1610 © IEC:1995 - 3
CONTENTS
Page
5
FOREWORD
Clause
1 Scope 7
7
2 Normative references
9
3 Terms and definitions
11
4 Conditions
11
Environmental conditions 4.1
11
4.2 Conditions of measurement
13
Conditions of calculation 4.3
15
5 Methods of measurements
15
5.1 Gamut of colours
5.2 Reproduced colours 25
31
Colour rendering 5.3
33
5.4 Grey balance
Grey scale reproduction (tone reproduction) 35
5.5
37 5.6 Grey non-uniformity
41
Resolution 5.7
43 Image stability under exposure to light (light fastness)
5.8
47
Image stability under exposure to heat (heat fastness) 5.9
49
5.10 Reproducible dimensional r ange
51
5.11 Flat field modulation
5.12 Contouring 57
59
5.13 Spatial linearity
61 5.14 Misregistration
Annexes
67
Specification of the input signal for the measurement of reproduced colours
A
69
B Bibliography
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- 5
1610 © IEC:1995
INTERNATIONAL ELECTROTECHNICAL COMMISSION
PRINTS AND TRANSPARENCIES
-
PRODUCED FROM ELECTRONIC SOURCES
ASSESSMENT OF IMAGE QUALITY
FOREWORD
ational Electrotechnical Commission) is a worldwide organization for standardization comprising
1) The IEC (Intern
the IEC is to promote
all national electrotechnical committees (IEC National Committees). The object of
the electrical and electronic fields. To this
ational co-operation on all questions concerning standardization in
intern
ational Standards. Their preparation is entrusted to
in addition to other activities, the IEC publishes Intern
end and
subject dealt with may participate in this
the
technical committees; any IEC National Committee interested in
non-governmental organizations liaising with the IEC also
preparatory work. International, governmental and
e Inte ational Organization for Standardization
participate in this preparation. The IEC collaborates closely with th rn
greement between the two organizations.
(ISO) in accordance with conditions determined by a
ress as nearly as possible, an international
2) The formal decisions or agreements of the IEC on technical matters, exp
relevant subjects since each technical committee has representation from all interested
the
consensus of opinion on
National Committees.
rnational use and are published in the form
The documents produced have the form of recommendations for inte
3)
e National Committees in that sense.
of standards, technical reports or guides and they are accepted by th
rnational
ational unification, IEC National Committees undertake to apply IEC Inte
4) In order to promote inte rn
maximum extent possible in their national and regional st andards. Any divergence
andards transparently to the
St
dard shall be clearly indicated in the
andard and the corresponding national or regional st an
between the IEC St
latter.
and cannot be rendered responsible for any
5) The IEC provides no marking procedure to indicate its approval
equipment declared to be in conformity with one of its standards.
elements of this Inte rnational Standard may be the subject of
Attention is drawn to the possibility that some of the
6)
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
rnational Standard IEC 1610 has been prepared by IEC technical committee 84: Equipment
Inte
and systems in the field of audio, video and audiovisual engineering.
The text of this standard is based upon the following documents:
Report on voting
FDIS
84 /443/RVD
84/399 /1-VIS
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
Annex A forms an integral part of this standard.
Annex B is for information only.
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1610 © IEC:1995 - 7
PRINTS AND TRANSPARENCIES
PRODUCED FROM ELECTRONIC SOURCES —
ASSESSMENT OF IMAGE QUALITY
1 Scope
This International Standard applies to the assessment of image attributes on prints and
transparencies produced from electronic sources. Assessment of the equipment itself which
produces prints and transparencies is outside the scope.
and
This standard specifies test signals, measurement conditions forms of reporting the results so
as to make possible the comparison of the results of measurements. The methods of measurement
are designed to make possible the assessment of the image quality of prints and transparencies
produced from electronic sources. The electronic sources are either an alogue or digital signals of
tran
defined format, whose corresponding images are reproduced on either a sparent or a
non-transparent medium.
andard are designed to be applicable to a wide quality r ange
The methods of measurement in this st
of colour prints and transparencies. This range runs from a small piece of image for consumer use
to a large and precise image for professional use. The prints and transparencies may be produced
either by colour video printers with analogue inputs for consumer use, by professional colour
image printers with digital inputs or by any other electronic means.
This standard does not specify limiting values for various parameters.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this International Standard. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and pa rties to agreements
ational Standard are encouraged to investigate the possibility of applying the
based on this Intern
most recent editions of the normative documents indicated below. Members of IEC and ISO
maintain registers of currently valid Inte rnational Standards.
International Electrotechnical Vocabulary (IEV) Chapter 845: Lighting
IEC 50(845): 1987,
ISO 5-1: 1984, Photography – Density measurements – Part 1: Terms, symbols and notations
Photography – Density measurements – Part 2: Geometric conditions for
ISO 5-2: 1991,
transmission density
ISO 5-3: 1984, Photography – Density measurements – Part 3: Spectral conditions
Photography – Density measurements – Part 4: Geometric conditions for
ISO 5-4: 1983,
reflection density
ISO/CIE' 10526: 1991, CIE standard for colorimetric illuminants
1) CIE stands for the International Commission on Illumination.
---------------------- Page: 5 ----------------------
1610 © IEC:1995 - 9
ISO/CIE 10527: 1991, CIE standard colorimetric observers
CIE 15.1: 1972, Special metamerism index: Change in illuminant
CIE 15.2: 1986, Colorimetry
Special metamerism index: Change in obse rver
CIE Technical Report 80: 1989,
Nomenclature and description of colour bar signals
ITU-le Recommendation BT 471-1: 1990,
Terms and definitions
3
ational Standard, the following definitions apply.
For the purpose of this Intern
Visible, two-dimensional representation of electronic signals intended to form a
3.1 image:
picture.
Apparatus which supplies electronic signals of analogue or digital form
3.2 electronic source:
input to equipment that produces coloured images.
carrying colorimetric information to be used as
an image.
Substance within which the equipment produces
3.3 medium:
for a medium.
substrate: Substance providing support
3.4
ce of the image-making
an electronic source to enable the perform an
3.5 test signal: Output of
equipment to be assessed.
opaque substrate.
Reproduced image formed on an
3.6 print:
ansparent substrate.
transparency: Reproduced image formed on a tr
3.7
image quality: Objective quality of an image.
3.8
ase ten of the reciprocal of definite integral of the
3.9 integrated density: Logarithm to b
dard luminous efficiency function with the spectr al reflectance or
spectral product of the CIE st an
transmittance.
spectral
NOTE – The notations for integrated densities are modified from those specified in ISO 5-1 for the sake of
avoiding confusion.
Three-dimensional maximum range of reproducible colours expressed
gamut of colours:
3.10
colour space defined in CIE 15.2.
in CIE 1976 L `a`b *
Colours produced by signals from the electronic source, which when
3.11 primary colours:
formed by the additive process are red, green and blue, or by the subtractive process are yellow,
cyan and magenta.
Colours produced by a mixture of two primary colours.
3.12 secondary colours:
Reproduced primary colours and secondary colours.
3.13 saturated colours:
NOTE – Saturation means the maximum excitation purity (chromaticity), limited by each specific system.
Formerly CCIR Recommendation.
1)
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1610 © IEC:1995 - 11 -
3.14 colour bars: Test signal which carries colorimetric information on black, white and
saturated colours.
3.15 reproduced colours: Colorimetric information measured from the reproduced image
L *
expressed in CIE 1976 a*b * colour space which is defined in CIE 15.2.
3.16 tone reproduction: Colorimetric relation between a test signal which is intended to produce
d
an achromatic image an the image actually produced.
4 Conditions
4.1 Environmental conditions
All measurements shall be carried out within the environmental conditions as specified by the
d transparencies, unless otherwise
manufacturer of the equipment which produces prints an
specified by this st andard.
The environmental conditions during measurement, at least the room temperature and the relative
humidity, shall be reported together with the presentation of the results of measurements.
4.2 Conditions of measurement
al
Any adjustable parameters shall be set to the manufacturer's recommended or defaults v ues. An
adequate warm-up time shall be allowed.
The test images shall be produced by applying the test signals to the equipment following the
manufacturer's specification. The medium on which the images are produced shall be the one
specified by the manufacturer of the equipment.
The measurements of image quality of prints and transparencies shall be carried out by measuring
tral density and
the optical characteristics of reflectance or transmittance, respectively. Optical spec
an
integrated density may be used for specific measurements in this st dard.
Each test signal of known characteristics shall be generated to produce the image which is
specified in this standard. The image shall be measured without any time interv al, unless otherwise
specified. Spectral radiation or spectr al reflectance should be measured over the wavelengths from
360 nm to 780 nm, but shall be measured at least from 400 nm to 700 nm in 10 nm, and 5 nm
steps for incandescent lamps and fluorescent lamps, respectively.
If the input signal to equipment which produces prints or transparencies is expressed in a set of
digital codes whose colorimetric coordinate values for four colours (white, red, green and blue)
in the CIE 1931 xy chromaticity diagram defined in CIE 15.2 are different from those
dard colours for conventional television systems [1]*, these values shall
corresponding to the st an
an blue.
be specified by the manufacturer of the equipment for the four colours: white, red, green, d
These coordinate values shall be used to translate the actual input information to corresponding
tristimulus values by the method given in [2] to obtain the conversion coefficients.
* Numbers in square brackets refer to annex B, Bibliography.
---------------------- Page: 7 ----------------------
1610 © IEC:1995 - 13 -
NOTES
al reflectance should be measured using a spectrophotometer with either 0/5 or 45/0 geometry as
1 The spectr
stated in ISO 5-4.
the
2 Reflectance (optical) density is defined as logarithm to base ten of the reciprocal of reflectance
the reflectance is composed of regular reflectance and diffuse
[IEV 845-04-65]. The IEV also states that
the instruments and the
and that the results of measurements of these reflectances depend on
reflectance,
measuring techniques used [IEV 845-04-62]. The same applies for transmittance (optical) density
[IEV 845-04-66, IEV 845-04-59, IEV 845-04-63].
calculation
4.3 Conditions of
4.3.1 Illuminants and colorimetric observers
andard
ant C or D65 defined in ISO/CIE 10526 and the CIE 1931 st
The CIE standard i llumin
colorimetric observer defined for a view angle of 2° in ISO/CIE 10527 should be used for
lluminant is used, it shall be reported. For
calculation of the tristimulus v alues. If any another i
reflective density may be used, but it
some measurements, optical transmittance density and
should be noted that the measured values depend on the instruments used for the measurement.
4.3.2 Tristimulus values
t colours shall be calculated by the
and illuminan
The tristimulus values for object colours
al
al radiation, S(A), of the st andard illuminant, the spectr
summations of the products of the spectr
the colour matching functions, x(71) , y(71) , z(11) as
transmittance or reflectance, p(A), and
defined by the following formulae:
1
p(1) ;(l) dl
- 1
X=
S ( )
K vis
1
1 l ,1) dl
Y= f S( ) p ( ) Y(
vis
K
1
p(I) z(,l) dl
OL
Z = f S )
vis
K
where
= f ^.
K
S(^ ) y(^) d
v,s
as the CIE 1931 standard colorimetric
x(1), y(1) and z(a.) are the functions specified
angle of 2° (see ISO/CIE 10527).
observer for a view
Relation between input values and tristimulus values
4.3.3
is a standard analogue or digital video signal, the appropriate colorimetric
al
When the input sign
specification should be used to transform corresponding tristimulus values. The conversions from
ues shall be made by the following equations according to the video
to the tristimulus val
R, G, B
standard used.
---------------------- Page: 8 ----------------------
- 15 -
1610 © IEC:1995
For standard NTSC system with standard illuminant C
G + 0,20025 B
X = 0,60674 R + 0,17353
B
Y= 0,29884 R + 0,58673 G + 0,11443
0,06611 G + 1,11566 B
Z= 0,00000 R+
/SECAM systems with standard illuminant
For standard PAL
D65
R+ 0,34155 G+ 0,17819 B
X= 0,43066
B
Y = 0,22206 R + 0,70666 G + 0,07128
R + 0,12956 G + 0,93848 B
Z = 0,02019
For any standard HDTV system
The equations should be decided in accordance with the chromaticity coordinate values for
d for the reference white, in accordance with the method
the input primary colours, an
described in [2].
5 Methods of measurements
5.1 Gamut of colours
5.1.1 Characteristics to be determined
chromaticity.
ange in terms of the psychometric lightness and
The maximum reproducible colour r
Measurement procedure
5.1.2
as specified by this
a) The test signals containing input saturated colours shall be generated
standard.The signals shall correspond to the colours white, yellow, cyan, green, magenta,
and black as prints and transparencies.
red, blue,
The level of each input signal shall be in accordance with table 1.
---------------------- Page: 9 ----------------------
1610 © IEC:1995 - 17 -
Table 1– Input signal specification
Input signals
Colours %
R G B
1 White 100 100 100
100 0
2 Yellow 100
3 Cyan 0 100 100
4 Green 0 100 0
5 Magenta 100 0 100
0
6 Red 100 0
7 Blue 0 0 100
0
8 Black 0 0
If the equipment accepts standard video signals, the standard colour bar generator to
produce colour bars (a) 100/0/100/0 (see ITU-R Recommendation BT 471-1) may be used.
b) The spectral density d(A), or spectral reflectance or spec tral transmittance p(2), for
lluminant colours of transparencies, corresponding to the test
object colours of the prints or i
signals, shall be measured for wavelengths from 400 nm to 700 nm in 10 nm steps.
al
If spectral density is adopted for the measurement, it shall be converted to spectr
reflectance or transmittance by the following formula:
(I) = 10 ^(z)
p
shall be calculated for each colour (see 4.3.2).
c) The tristimulus values, X, Y, Z
5.1.3 Presentation of results
and black, shall be
The measured spectral characteristics for the eight colours, including white
as the curves (see figure 1). The calculated tristimulus v alues shall be converted to values
plotted
defined in CIE 15.2 for eight colours. They shall be
in the CIE 1976 colour space, L *a*b * as
as a table (see table 2), together with the kind of the st andard illuminant used for
reported
as graphs, as shown in figure 2.
calculation. The results shall also be presented
116,0 Y'-16,0
L' =
a ' = 500 ,0(X'-Y')
200 ,0(Y'-Z')
b ' =
---------------------- Page: 10 ----------------------
1610 © IEC:1995 - 19 -
where
^
X^ = ( X )' for X z 0,008856
Xn X.
1
9
Y i _ (Y ) for Y z 0,008856
Yn Yn
1
Z
s
Z ^ = (? ) for z 0,008856
Z n Z n
and
X 16,0 X
^
X' - 7,787 for — 0,008856
X. 116 ,0 X.
Y ^ 16,0
Y
Y' - 7,787 for s 0,008856
Yn 116 ,0 Yn
Z 16 ,0 Z
Z' - 7,787 , for s 0,008856
Z n 116 ,0 Zn
and where X Y Zn are the tristimulus values for the illumin ant of the colorimetric system
adopted for the input signal.
For the NTSC system:
Xn = 0,98054
Y. = 1,00000
Zn = 1,18181
For the PAL/SECAM system:
Xn = 0,95041
Yn = 1,00000
Zn = 1,08825
For the systems other than the above, taking into account the specific illuminant, S(2):
S(1) x(A) dA
f
- °is
X
n
dA
S(1l) y(A)
f
^
Y n = 1,00000
S(A) z(A) dl
f^
S(A) y(A) dA
f
J vis
---------------------- Page: 11 ----------------------
1610 © IEC:1995 -21 -
600 650 700
450 500 550
400
Wavelength (mm)
Figure 1– Spectral characteristics of saturated colours
Table 2 – Tabular report for gamut of colours
L` a`
Colours b*
'White
Yellow
Cyan
Green
Magenta
Red
Blue
Black
Standard illuminant:
---------------------- Page: 12 ----------------------
1610 ©
IEC:1995 - 23 -
r
r i
1
.+.Y
100
50
-
G+
. .+ R
0
b*
• +W
K
C}.
.4t-
,+•
-50
- B -
-100
I i
I 1
-100
-50 0 50
100
a*
Figure 2a - Gamut of colours expressed in (41)) plane
100
W
oYo
80
60 oC
G o M
L*
0
0
40
Bo
R
0
K
20
0
-100 0
-50 50 100
a*
Figure 2b - Gamut of colours expressed in (a* ,L*) plane
---------------------- Page: 13 ----------------------
1610 © IEC:1995 - 25 -
100
w
Y*
80
60
Co
G
L*
Mo
o
40
Bo
R
o
20
K
0
-100 -50 0 50 100
b*
Figure 2c - Gamut of colours expressed in (b ,L`) plane
Figure 2 – Gamut of colours
5.2 Reproduced colours
5.2.1 Characteristics to be determined
Coordinate points in CIE 1976 L *a*b * colour space (defined in CIE 15.2) of unsaturated primary
colours, yellow, magenta and cyan, and unsaturated secondary colours, red, green and blue, and
white, when the specified input signals are applied to the equipment which produces prints or
transparencies.
5.2.2 Measurement procedure
a) The test signals containing colorimetric information, X o, 1', Zo, in tristimulus values
specified in this standard shall be generated to produce prints and transparencies. The
specifications of the tristimulus values are stated in annex A.
If the equipment accepts a composite colour video sign al, the corresponding sign al may be
generated by the standard 100/0/100/0 colour bar generator to generate test pattern (a) of
chrominance signal level attenuated by one-half
ITU-R Recommendation BT 471-1 with the
in amplitude, and with the luminance signal level unchanged. If the equipment accepts
component video, the R, G, B test signal shall be in accordance with the table in annex A.
---------------------- Page: 14 ----------------------
1610 © IEC:1995 - 27 -
b) The prints and transparencies corresponding to the test signals shall be measured to
obtain the tristimulus values, X m, Ym, Zm, for illuminant colours and for object colours,
respectively (see 4.3.1 and 4.3.2).
c) The tristimulus values of the reproduced colours, X m, Ym, Zm, shall be converted to the
CIE 1976 colour space, L *a *b * (see 5.1.3).
5.2.3 Presentation of results
The calculated L * b * shall be reported together with the st andard illuminant used in calculation,
as in table 3. The coordinate points in the two-dimensional chromaticity scales shall also be
reported as shown in figure 3.
Table 3 – Tabular report for reproduced colours
Couleurs L* a* b*
White
Yellow
Cyan
Green
Magenta
Red
Blue
Black
Standard illuminant:
80
i 1
i i i i
60
_ _
o Y
40
_ o G
20
oR
W
0
b*
0
_ Co
-20
oM -
- o B _
-40
-60
I I
I I I 1
-80
-80 -60 -40 -20 0 20 40 60 80
a*
Figure 3a - Reproduced colours in (a*,b *) plane
---------------------- Page: 15 ----------------------
IEC:1995 - 29 -
1610 ©
100 , 1 I I I I
oyo
W
o
80 o
60
o
M
o
L*
R
40 -
o
20
i i 1 t
0
-80 -60 -40 -20 0 20 40 60 80
a'
Figure 3b - Reproduced colours in (a L) * plane
i i i
100
I I
o
c W
o C
oG
80
60
o
M
0
R
L*
o
40
20
1
I
0
20 40 60 80 -80 -60 -40 -20 0
b*
`) plane
Figure 3c - Reproduced colours in (b ,L
Figure 3 – Reproduction of colours
---------------------- Page: 16 ----------------------
1610 © IEC:1995 - 31 -
5.3 Colour rendering
The colour images are sometimes viewed in different colorimetric conditions, namely under
illuminants other than the specific st andard illuminant and by observers of various ages, which are
modelled as the standard deviate observer as defined in CIE Technical Repo rt 80. They cause an
apparent colour shift from the intended colour.
5.3.1 Characteristics to be determined
The apparent colour shift of the reproduced colour image due to ch anges in illuminant or in
observer.
5.3.2
Measurement procedures
a) Lack of colour rendering under change in illumin ants
1) The spectral reflectance and the spectral transmittance, p(A), of the reproduced
colours in prints and transparencies, respectively, produced for the reproduced colours
of 5.2 shall be used with different illumin ants, S'(2), other than the standard illuminants
C or D65, to calculate the shifted tristimulus values.
2) The shifted tristimulus values shall be calculated for the following illuminants: the CIE
dard illumin supplementary standard illuminant D50 theee additional
stan ant A, the CIE and
illuminants, F2 (normal fluorescent lamps), F7 (high-rendition fluorescent lamps), and
Fl (three-wavelength fluorescent lamps) as recommended by CIE 15.1.
3) The colour shift, AL*, Aa *, Ab * from the original reproduced colour shall be obtained
in the CIE 1976 colour space L *a*b* for each colour.
ange in observer
b) Lack of colour rendering under ch
1) The spectral reflectance and the spec tral transmittance, p(A.), of the reproduced
colours in prints and transparencies, respectively, produced for the reproduced colours
of 5.2 shall be used with the CIE standard deviate observer defined in CIE Technical
Report 80 and with the standard illuminants C or D65, to calculate the shifted tristimulus
values as
in the following formulas :
+
X- 1 1 1 (x(,l) 1 dl
S( ) p ( ) Oxl( ))
f^
K
1
+ (x)) dl
Y =— 1 I eyl
( (Y())
S( ) p )
l
K uis
1 I ez 1 dl
Z= 1 f S( ) p ( ) (z(ll) + ,( ))
K vis
---------------------- Page: 17 ----------------------
1610 © IEC:1995 - 33 -
where ex-10.), ey,(x) and Az,(.) are the functions to characterize the st andard deviate
observer, and
K= S(A)y(A)da.
vu
f
2) The colour shift AL*, za , Ab * from the original reproduced colour shall be determined
in the CIE 1976 colour space L *a*b * for each colour.
5.3.3 Presentation of results
anges in illuminants and in observer shall be reported together
The degree of colour shift under ch
with the standard illuminant in a table such as table 4.
Table 4 — Colour shift report
Illuminant AL* Aa* A b*
A
D50
F2
F7
F11
Standard illuminant:
Colour shift caused by the change in observer
AL*. ; AE ;A b*= *ab=
; Aa*=
5.4 Grey balance
5.4.1 Characteristics to be determined
The degree of achromatic b alance when achromatic input signals are reproduced as prints or
transparencies.
Measurement procedure
5.4.2
a) The achromatic signal shall be generated following what the manufacturer specifies for
the equipment.
The achromatic signal shall include grey levels from 0 % to 100 % of the input full-scale
b)
ranges in 20 % steps inclusively.
e equations shown in 4.3.3 when they are of the
NOTE — The achromatic signal levels are calculated by th
standard video signals, or in accordance with 4.3.2 when they are arbitrarily defined.
c) The images shall be measured for their spectr al transmittance of transparencies or spectral
reflectance of prints.
d) The tristimulus values corresponding to each grey level shall be calculated and converted
L *a*b * (see 5.1.3).
to coordinate values in the CIE 1976 colour space
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1610 © IEC:1995
5.4.3 Presentation of results
The degree of achromatic balance shall be reported as plots on the (a*,b *) coordinates and as plots
on the (C *,L*) coordinates, where C is defined as:
•24, •2
C` =
100
25
I I I I
I I I I
o
20
80
15
o
10
0
60
5
0
L*
0
b*
o
40
-5
o
-10
20
-15
-20
1 1
1 1 i i i
-25
5 10 15 20 25
- 20-15-10 -5 0 5 10 15 20 25
25 -
b*2
a* C* = Va*2 +
Figure 4 – Presentation of grey balance
Grey scale reproduction (tone reproduction)
5.5
5.5.1 Characteristics to be determined
The linearity of the psychometric lightness when achromatic input signals of various levels are
reproduced.
5.5.2 Measurement procedure
an
a) The achromatic sign al shall be generated following what the m ufacturer specifies for
the equipment.
b) The achromatic signal shall be composed of grey levels from 0 % to 100 % of the input
full-scale ranges in 10 % steps, inclusively.
NOTE – The achromatic signal levels are calculated by the equations shown in 4.3.3 when they are of the
standard video signals, or in accordance with 4.3.2 when they are arbitrarily defined.
c) The reproduced images shall be measured by their reflectance optical densities
D t (S
D r (SA : v), for prints, or transmittance optical densities a : V T), for transparencies, for
each step i. For the notations, see ISO 5-1.
The measuring instrument shall have a spectral product, II v response, equal to the spectral
product of the CIE standard luminous efficiency function, V(A) (see ISO/CIE 10257) and
the spectrum of the CIE standard illuminant A (see ISO/CIE 10256).
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1610 © IEC:1995 - 37 -
NOTE – One of the tristimulus values Y, may be measured instead of density. If this is
the case, the density D;
should be calculated by the following equation:
Y
D.=-
logio
5.5.3
Presentation of results
A : To D t (S 11 : V T)i
The measured density data, D r (S i for prints or for transparencies, shall be
plotted versus input signal levels.
NOTE – The achromatic signal levels are calculated by the equations shown in 4.3.3 when they are of the
standard video signals, or in accordance with 4.3.2 when they are arbitrarily defined.
2,5
Density 1,5
0,5
20 40 60 80 100
Signal level (%)
Figure 5 – Presentation of grey scale reproduction
5.6 Grey non-uniformity
5.6.1 Characteristics to be determined
The full image non-uniformity when a constant achromatic signal is reproduced as uniform
grey prints or transparencies.
5.6.2 Measurement procedure
a) Generate the achromatic signal which produces prints or transparencies of reflectance
optical density D r (S A :V) = 0,3 or transmittance optical density D t (SH : VT) = 0,3 .
The measuring instrument shall have the same spectral response as the CIE standard
luminous efficiency function, V(.l).
b) The signal level shall be adjusted to the required level by interpolating the data
obtained in 5.5.
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1610 © IEC:1995 - 39 -
c) The reproduced images shall be measured by their reflectance optical densities
D r (S A : V), H T
for prints, or transmittance optical densities D t (S : V ), for transparencies, at
the centre ( i= 0) and near the four corners, at the positions (i = 1,2,3,4) shown in
figure 6.
NOTE — The achromatic signal levels are calculated by the equations shown in 4.3.3 when they are of the
standard video signals, or in accordance with 4.3.2 when they are arbitrarily defined.
5.6.3 Presentation of results
The non-uniformities in terms of optical density of prints or transparencies shall be reported as
the differences, AD ri or ADti, of the corners from the cen tre (see table 5).
V)0
AD V). -
r; = D r(S A : D r(S A :
ADti = D t(S H
...
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