Color Analysis – CIE94 (ASTM E with ASTM D). Color Analysis – Hunter (ASTM E & ASTM D). Scope: Hunter Lab and XYZ are standard . This standard is issued under the fixed designation D ; the number 1 This practice is under the jurisdiction of ASTM Committee E12 on Color and. ASTM D Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates.
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Color Analysis – CIE94 (ASTM E1347 with ASTM D2244)
The CIELAB color-difference equation is also not recommended in this practice for use in describing small and moderate color differences differences with magnitude less than 5. The CMC components and single number tolerances are computed as follows: Good correlation with the visual judgments may not be obtained when the calculations are made with other illuminants. Current color tolerance r2244 equations which base the distortion of CIELAB space on the position of the standard allows a user to prede?
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While the CIELAB equation has not completely replaced the use of Hunter LH, aH, bH, this older scale is no longer recommended for other than legacy users, and is therefore included in an Appendix for historical purposes. Under these conditions, Xn, Yn, Zn are the tristimulus values of the standard illuminant with Yn equal aetm Each subsequent color scale based on CIE values has had weighting factors applied to provide some degree of uniformity so that color differences in various regions of color space will be more nearly comparable.
This standard is subject to revision at any time by the responsible technical committee and must be reviewed every?
Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm. The color dependent functions are de?
By using the position of the arithmetic average color between the two specimens to compute the local distortions to CIELAB color space, the roles of the two specimens may be switched without changing the magnitude of the computed colordifference, in full agreement with the visual assessments.
Standards can be obtained from appropriate standards authorities. Thus d22444 color differences are based only on the Euclidean distance in the DIN99 space. ASTM D von Colorimetric spectrometers are designed to optimize their use as digital simulations of the visual colorimeter or as the source of spectral and colorimetric information for computer-assisted color matching systems.
To avoid confusion, color differences among specimens or the associated tolerances should be compared only when they are obtained for the same asfm system. Usually, the white object-color stimulus is given by the spectral radiant power of one of the CIE standard illuminants, for example, C, D65 or another phase of daylight, re?
Visual color and spectrophotometer readings can also be affected by surface texture, molding parameters, processing dd2244, and viewing light sources. Evaluating how your products and services meet and exceed quality, safety, sustainability and performance standards. The three tolerance equations given here have been tested extensively against such data for textiles and plastics and have been shown to agree with the visual evaluations to within the experimental uncertainty of the visual judgments.
ASTM D – COLOR DETERMINATION
On the other hand, color differences obtained for the same specimens evaluated in different color-scale systems are not likely to be identical. A superscript epsilon e indicates an editorial change since the last revision or reapproval. Through our network of over 43, people in 1, laboratories and offices in countries, Intertek provides quality and safety solutions to a wide range of industries around the world. This standard has been approved for use by agencies of the Department of Defense.
Inter-changing the reference and test specimens does not change either the perceived or predicted color differences.
See Practice E The four color space terms are computed as follows: Lightness L99 5 Need help or have a question? Assurance Enabling you to identify r2244 mitigate the intrinsic risk in your operations, supply chains and business processes.
All the k values default to 1 in the absence of speci?
It was derived primarily from visual observations of automotive paints on steel panels. There is no simple factor that can be used to convert accurately color differences or color tolerances in one system to difference or tolerance units in another system for all aztm of specimens.
For specimens that are matte, randomly rough, or mildly textured, values intermediate between 1: Validating the specifications, value and safety of your raw materials, products and assets. Nor is it possible or reasonable to plot groups of asm in terms of the modi? Current edition approved May 1, There should not be a need to break the equation down into perceptual components—the CIELAB components of the model do that already.
On the asm hand, color differences obtained for the same specimens evaluated in different color-scale systems are not likely to be identical.
Historical Version s – view previous versions of standard. ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. However, for control of color in production, it may be necessary to know not only the magnitude of the departure from standard but also the direction of this departure. Table 2 gives the mean color differences and their standard deviations for the groups of instruments considered While not obvious from this listing, all displayed angles are assumed to be given in degrees, including Du and thus must generally be converted into radians for trigonometric analysis on digital computers.
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