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Colorimetry - Part 1: CIE Standard Colorimetric
Observers CIE Standard S 014-1/E:2006
Colorimetry
- Part 2: CIE Standard Illuminants CIE Standard S 014-2/E:2006
Proceedings of the ISCC/CIE Expert Symposium
'06, 75 Years of the CIE Standard Colorimetric Observer 16-17
May 2006, Ottawa, Ontario, Canada
Geometric Tolerances for Colour Measurements
CIE 176:2006
A Framework
for the Measurement of Visual Appearance CIE 175:2006
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Colorimetry - Part
1: CIE Standard Colorimetric Observers CIE Standard S 014-1/E:2006
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This CIE Standard replaces ISO/CIE 10527:1991. This Standard
contains only minor changes from
the previous Standard, it has now been clarified that the values
of the colour matching functions apply for standard air to make
the Standard conform to other CIE photometric and colorimetric data.
Colours with different spectral compositions can look alike. An
important function of colorimetry is to
determine whether a pair of such metameric colours will look alike.
It has long been the practice in
colorimetry to make use of sets of colour-matching functions to
calculate tristimulus values for colours:
equality of tristimulus values for a pair of colours indicates that
the colour appearances of the two colours match, when they are viewed
in the same conditions by an observer for whom the colour-matching
functions apply. The use of standard sets of colour-matching functions
makes the comparison of tristimulus values obtained at different
times and locations possible.
This International Standard specifies colour-matching functions
for use in colorimetry. Two sets of
colour-matching functions are specified:
Colour-matching functions for the CIE 1931 standard colorimetric
observer
This set of colour-matching functions is representative of the colour-matching
properties of observers
with normal colour vision for visual field sizes of angular subtense
from about 1° to about 4°, for vision at
photopic levels of adaptation.
Colour-matching functions for the CIE 1964 supplementary
standard colorimetric observer
This set of colour-matching functions is representative of the
colour-matching properties of observers
with normal colour vision for visual field sizes of angular subtense
greater than about 4°, for vision at sufficiently high photopic
levels and with spectral power distributions such that no participation
of the rod receptors of the retina is to be expected.
The values in the tables of the colour matching functions and chromaticity
coordinates of the CIE
1931 and 1964 standard colorimetric observers are identical with
those in the previous standard.
This standard has been approved by CIE National Committees. It may
be obtained via the website of
the Central Bureau of the CIE (www.cie.co.at).
Price of this standard: EUR 48,- (Members of national CIE organisations
get 50% discount).
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Colorimetry
- Part 2: CIE Standard Illuminants
CIE Standard S 014-2/E:2006 |
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This CIE Standard replaces ISO 10526:1999/CIE S005:1998. It contains
only minor changes from
the previous standard, mainly concerning the wavelengths that are
to be taken as being in standard air, to
make the Standard conform to other CIE photometric and colorimetric
data.
CIE standard illuminants are used in colorimetry to compute the tristimulus
values of reflected or
transmitted object colours under specified conditions of illumination.
This International Standard specifies
two illuminants for use in colorimetry:
CIE standard
illuminant A
This is intended to represent typical, domestic, tungsten-filament
lighting. CIE standard illuminant A
should be used in all applications of colorimetry involving the use
of incandescent lighting, unless there are
specific reasons for using a different illuminant.
CIE
standard illuminant D65
This is intended to represent average daylight. CIE standard illuminant
D65 should be used in all
colorimetric calculations requiring representative daylight, unless
there are specific reasons for using a different illuminant. Variations
in the relative spectral power distribution of daylight are known
to occur, particularly in the ultraviolet spectral region, as a function
of season, time of day, and geographic location. However, CIE standard
illuminant D65 should be used pending the availability of additional
information on these variations.
The numerical values of the relative spectral distributions of standard
illuminants A and D65 defined by
this Standard are the same, within an accuracy of six significant
digits, as those defined in earlier versions of these illuminants.
This standard has been approved by CIE National Committees. It may
be obtained via the website of the
Central Bureau of the CIE (www.cie.co.at).
Price of this standard: EUR 38,- (Members of national CIE organisations
get 50% discount).
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Proceedings
of the ISCC/CIE Expert Symposium '06, 75 Years of the CIE Standard
Colorimetric Observer
16-17 May 2006, Ottawa, Ontario,
Canada |
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CIE Division 1 and ISCC jointly organized a symposium to celebrate
the 75th anniversary of the CIE
1931 Standard Colorimetric Observer, to discuss the many advances
that have been made since its
introduction, to understand the current state of colorimetry and colour
appearance, and to provide guidance on directions for future work.
The meeting was divided into seven main sessions:
- Standard Observer
- Colour Matching Functions
- Instruments and Standards
- Temporal and Spatial Issues
- Application of the Standard Observer
- Colour Appearance
- Colour Differences
- Colour Management
- Discussion and included a Poster Session.
A general theme throughout the discussion, that summarized the hot
topics of the symposium, was the
need for more comprehensive colour appearance and colour difference
models. The current models take into account only a relatively small
number of factors that can affect the appearance of objects and images.
It was recommended that models be developed that include the effect
of spatial and temporal factors, that are applicable to all levels
of illumination from photopic to scotopic, and that take into account
both normal variations in visual functions and changes in visual functions
with aging. A second theme was the assessment of visual appearance
and visual differences, or more specifically, the measurement of other
attributes of surfaces such as gloss, translucency and texture.
The Proceedings contains the full text of all the presented 27 papers
and 5 posters.
The publication consists of 200 pages with 158 figures and 22 tables.
A CD-ROM with all papers in a
searchable form is included. CIE x030:2006 is readily available via
the website of the Central Bureau of
the CIE (www.cie.co.at).
The price of this publication is EUR 128,— (Members of the CIE
National Committees get 50% discount).
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Geometric
Tolerances for Colour Measurements
CIE 176:2006 |
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In this publication the recommendations of the CIE Division 2 "Physical
Measurement of Light and
Radiation" are given on the definition of geometries for the
measurement of the colour of materials and the
tolerances around those fundamental definitions that are required
to provide an expected level of accuracy
and reproducibility.
This publication documents, for the first time, definitive definitions
of the geometric requirements for
instrumental colour measurements. It further defines three levels
of tolerances which will provide three
ranges of accuracy and reproducibility so as to clearly define what
is required for the highest level of interlaboratory agreement and
what will be acceptable for industrial or commercial applications
of basic
colorimetry.
The terms and symbols used in this report are intended to be consistent
with the existing standards
in the International Organisation for Standardisation (ISO) and in
particular with ISO standards 5-1 and
5-4.
The report is written in English, with a short summary in French and
German. It consists of 24 pages
with 5 figures and is readily available via the website of the Central
Bureau of the CIE (www.cie.co.at).
The price of this publication is EUR 44,-- (Members of the national
CIE organisations get 50% discount). |
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A Framework
for the Measurement of Visual Appearance
CIE 175:2006 |
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Visual appearance can be one of the most critical parameters affecting
customer choice and it needs,
therefore, to be quantifiable to ensure uniformity and reproducibility.
A starting point in assessing the
appearance of a consumer product might be the measurement of its colour.
A description of its total
appearance, however, cannot be achieved by the definition of colour
alone; other attributes of the material
from which it is fabricated contribute to the overall appearance.
Starting from a definition of soft metrology and a description of
measurement scales, this report
describes a framework on which a set of measurements could be made
to provide correlates of visual
appearance. It will be shown that the interactions between the various
components of the framework are
complex, that physical parameters relating to objects are influenced,
at the perception stage, by the
physiological response of the human visual system and, in addition
by the psychological aspects of human
learning, pattern, culture and tradition.
The result might be to conclude that an attempt to measure appearance
may be too bold a step to
take. Thus, a sub-framework is considered in terms of what can now
be measured, and what might be
measured after further investigation and research. By dealing with
the optical properties of materials it is
seen that there are, perhaps, four headings under which possible measures
might be made: colour, gloss,
translucency and texture. It is recognised that these measures are
not necessarily independent; colour
may influence gloss, colour will certainly influence translucency,
and texture is probably a function of all
three of the other measures.
Colour measurement, colorimetry, is based on the measurement of spectral
reflectance, and is an
established science that is possible using commercial instrumentation
available at reasonable cost. Two
shortcomings are identified. First, there are a number of modern materials
where colour measurements
made using a single pair of illumination/viewing angles is not sufficient
to describe the perceived colorimetric effect. Thus, measurement at
more illumination/viewing angle combinations is required. Second,
the traditional, CIE recommended colorimetric parameters, while providing
correlates of visual percepts, are not able to predict the absolute
appearance of a coloured sample: colour appearance models are now
able to do this.
The measurement of gloss is an established methodology but there is
some doubt as to the scientific
basis for making the measurements using the present method and attempts
are being made to define
alternative approaches. The extension of gloss measurement, which
is essentially a measurement made
at a specific angle depending on the apparent gloss of the sample,
to investigate the shape of the gloss
peak, should provide more information.
Translucency is a subjective term that relates to a scale of values
going from total opacity to total
transparency. This whole subject area needs investigation to find
a rigorous measurement solution that
will probably be industry specific.
Texture is a harder variable to measure. The advent of digital imaging
systems makes the acquisition
of images of materials relatively easy, assuming due consideration
is given to the resolution of the image
capturing device, be it a camera or a scanner. Characterising these
images to give accurate CIE based
colorimetry is now possible and the application of suitable analysis
software should be able to provide
measurement scales that relate to the perceived texture. The idea
of establishing a series of ‘standard’
textures has been suggested.
The report is written in English, with a short summary in French and
German. It consists of 92 pages
with 41 figures and 4 tables, and is readily available via the website
of the Central Bureau of the CIE
(www.cie.co.at).
The price of this publication is EUR 72,-- (Members of the national
CIE organisations get 50% discount). |
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