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					ASTM committee E12 Colour and Appearance
Michael Pointer, SDC representative to ASTM, reports on ASTM activity for the first half of 2007

ASTM International, originally known as the American Society for Testing and Materials, is one of the
largest voluntary standards development organisations in the world. Its activities cover a number of
industry sectors.

ASTM committee E12 covers colour and appearance, it’s scope is:

          to promote knowledge of appearance properties and characteristics and to
          encourage the improvement and development of standards for describing and
          evaluating the appearance properties (such as colour, gloss, opacity, and texture) of
          engineering materials by:

•   the stimulation and sponsoring of research into appearance problems;
•   formulating terms, nomenclature and definitions generally applicable for describing the appearance of
    engineering materials;
•   developing, or coordinating with technical committees, standards methods, recommended practices
    for measurement of fundamental and general appearance properties;
•   assisting the technical committees to improve appearance standards by advice, suggestions, and
    dissemination of information;
•   reviewing and recommending approval or revision of ASTM standards, existing or proposed, involving
    appearance factors; and
•   serving, with the approval of the ASTM Board of Directors, as liaison agent between the Society and
    other organisations in matters concerned with factors of appearance.

The committee has 13 active sub-committees listed below. I am a member of those marked with an
asterisk.

                    E12.01*        Terminology
                    E12.02*        Spectrophotometry and colorimetry
                    E12.03*        Geometry
                    E12.04*        Colour and appearance analysis
                    E12.05         Fluorescence
                    E12.06*        Image based colour measurement
                    E12.07*        Colour order systems
                    E12.08         High visibility materials
                    E12.10         Retroreflection
                    E12.11*        Visual methods
                    E12.12*        Measurement of metallic and pearlescent colours
                    E12.13         Photoluminescent safety markings
                    E12.14*        Multidimensional characteristics of appearance

Each sub-committee (SC) has a number of test methods and practices assigned to it. The subjects
covered by each SC, together with the current work in progress, are reported in the next section.




          © 2007 Society of Dyers and Colourists
Sub-committees
E12.01 Terminology
Scope: the development of terminology and definitions of terms and symbols; and the
         insurance of uniformity of usage in these matters and conformance with Society
         recommendations.

This sub-committee is responsible for one publication: E284 Standard Terminology on Appearance.

    •   New definitions agreed for appearance, face colour, luminance coefficient, sampling aperture and
        uncertainty.
    •   Main committee ballot on contrast ratio, colour angle, flake angle, anormal, anormal angle,
        aspecular and aspecular angle.

E12.02 Spectrophotometry and colorimetry
Scope: the development of methods of test and practices for spectral characteristics of color.

Subjects covered include: reference standards, measurement of reflectance and transmittance using
various geometries, using spectrophotometric data for calculating colorimetric coordinates, colour
difference evaluation and the use of tristimulus colorimeters.

    •   E1348 Standard Test Method for Transmittance and Color by Spectrophotometry Using
        Hemispherical Geometry has been re-approved. More information about the standard can be
        found on the ASTM website.
    •   Working on WK2896, a new standard test method for daytime colorimetric properties of
        retroreflective sheeting and marking materials for traffic control and personal safety applications
        using 45:normal geometry.

E12.03 Geometry
Scope: the study and description of the geometry of appearance, including gloss, lustre, haze,
        texture, turbidity, and directionality, and the development of methods of test and
        practices for analysing geometric properties and appearance attributes of objects and
        materials.

Subjects covered include: the selection of geometric conditions for the measurement of reflection and
transmission properties of materials, the measurement and calculation of the reflection characteristics of
metallic surfaces, the measurement of gloss by goniophotometry and the specification of the geometry for
observations and measurements to characterise the appearance of materials. The latter includes
commercially available multi-angle spectrophotometers.

    •   No minutes.

E12.04 Colour and appearance analysis
Scope: to develop and maintain standards leading to the numerical description of color and
         appearance including general procedures for appearance analysis, computational
         methods, color specification, color difference, data handling and issues of uncertainties.

Subjects covered include: colour-difference calculation, calculation of CIE colorimetry, yellowness and
whiteness indices, the effect of variability of colour measurement from multiple measurements, electronic
interchange of colour and appearance data, weighting factors for tristimulus colorimetry and the
performance of colorimeters, spectrocolorimeters and gonio-spectrocolorimeters.

    •   E2214, Standard Practice for Specifying and Verifying the Performance of Color Measuring
        Instruments has been revised and balloted.




          © 2007 Society of Dyers and Colourists
    •   E2222, Standard Practice for Host Computer Communication with Spectrometers for Color
        Measurements has been re-approved. This is a placeholder pending re-writing. More information
        about the standard can be found on the ASTM website.
    •   E1708, Standard Practice for Electronic Interchange of Color and Appearance Data is being
        balloted for re-approval as a place-holder until the ISO work is completed.

E12.05 Fluorescence
Scope: to develop standards describing the measurement, terminology, calibration and
         instrument procedures for measuring materials exhibiting fluorescence.

Subjects covered include: colour measurement of fluorescent specimens, identification of fluorescence in
object-colour specimens by spectrophotometry, measuring bispectral photometric data for evaluation of
fluorescent colour, computation of the colorimetry of fluorescent objects.

    •   No minutes.

E12.06 Image based colorimetry
Scope: the development of standard measurement methods, practices, and terminology
         pertaining to the appearance, performance modeling, and special characteristics of
         display devices (such as cathode ray tubes, flat panel displays and photographic
         imaging systems) and coordinating such activities with other organizations having
         similar interests.

Subjects covered include: obtaining colorimetric data from a visual display unit by spectroradiometry,
obtaining spectroradiometric data from radiant sources for colorimetry and obtaining colorimetric data
from a visual display unit using tristimulus colorimeters.

    •   Working on WK11946, Objective Quantification of Dental Plaque Using Digital Still Cameras.
    •   Working on WK11947, Objective Measurement of Gingival Color Using Digital Still Cameras.

E12.07 Colour order systems
Scope: to develop and maintain test methods, practices and guides relating to the use of colour
         order systems and determining the notations of colours in respect to various colour
         order systems. To serve as an advisory group to other organizations with an interest in
         colour order systems.

Subjects covered include: specifying colour using the Munsell System and the Optical Society of America
Uniform Color Scales System.

    •   Working on a revision of D1535 Standard Practice for Specifying Color by the Munsell System, to
        provide tristimulus values for the Munsell colours under illuminants other than Illuminant C. More
        information about the updated standard can be found on the ASTM website.
    •   E1541 Standard Practice for Specifying and Matching Color using the ColorCurve System has
        been withdrawn because the ColorCurve system is no longer available.

E12.11 Visual methods
Scope: the scope of the subcommittee shall be to examine appearance attributes of materials
         which do not currently lend themselves to instrumental evaluation and to derive visual
         methods by which these characteristics can be objectively described.
         Included in this scope shall be the development of standards related to characteristics
         of observers, specification of light sources not elsewhere specified, illuminating and
         viewing geometry and other conditions concerned with visual evaluation of materials.

Subjects include: the visual evaluation of colour differences, methods for the establishment of colour and
gloss tolerances, the visual evaluation of metamerism, visual evaluation of coloured transparent sheet



          © 2007 Society of Dyers and Colourists
materials, the selection, evaluation and training of observers for visual experiments and the design and
conduct of visual experiments, the selection and calibration of sources for the visual assessment of object
colours.

    •   D4086 Standard Practice for Visual Evaluation of Metamerism has been re-approved. More
        information about the updated standard can be found on the ASTM website.
    •   Working on WK4911, a standard practice for estimating the colorimetric effects of light-on-object
        colours.

E12.12 Measurement of metallic and pearlescent colours
Scope: not stated.

Subjects include: multi-angle measurement of metal flake pigmented materials, viewing conditions,
pearlescent and other interference flakes.

    •   Ballot on latest version of WK1164, a new standard practice for multi-angle colour measurement
        of interference pigments.

E12.14 Multidimensional characteristics of appearance
Scope: not stated.

This sub-committee has no allotted standards.

    •   Working on a practical experiment to establish tolerances for the assessment of distinctness-of-
        image.

E12.93 Precision and bias
Scope: not stated.

    •   This sub-committee is working on a new practice for conducting an inter-laboratory study to
        determine the precision of a test method with multi-varied measurands. The sub-committee is
        finding it difficult to get consensus on this subject and has recently established two working
        groups to investigate specific issues to do with bias and uncertainty.




          © 2007 Society of Dyers and Colourists