ASTM D2244 PDF

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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Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm. Inspection Validating the specifications, value and safety of your raw materials, products and assets.

That implies that the equations themselves misclassify a color difference with ast, frequency no greater than that of the most experienced visual color matcher. Send us a request Wilton UK: It was derived primarily from visual observations of automotive paints on steel panels. This is contrary to what is observed. Thus the equation is highly optimized for pairwise comparison of a product standard to a production test specimen but not for statistical process control.

Visually, there is no change in the magnitude of the difference between the specimens simply by switching roles. 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 asmt agreement with the visual assessments.

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ASTM D2244

On the other hand, color differences obtained for the same specimens evaluated in different color-scale systems are not likely to be identical. There should not be a need to break the equation down into perceptual components—the CIELAB components of the model do that already. The most common values are 2: Both are appropriate for and widely used in industrial and commercial applications including, but not limited to, automobiles, coatings, cosmetics, inks, packaging, paints, plastics, printing, security, and textiles.

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It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use. Specular component included for integrating-sphere measurements.

ASTM D ColorTolerance_百度文库

This method of computing a metric hue difference loses the information about the sign of the hue difference positive or negative and can be unstable for pairs of colors near the neutral axis.

Send us a request Need help or have a question? Color-difference units are computed, from these color-scale values, and approximate the perceived color differences between the reference and the test specimen. Assurance Testing Inspection Certification. Inter-changing the reference and test specimens does not change either the perceived or predicted color differences. See Practice E A number in parentheses indicates the year of last reapproval.

Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. Consequently, color differences are seldom if ever computed directly from differences asm x, y, and Y. Need help or have a question? Those conditions are given in Table 1.

Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. Record the location where these measurements were made on the specimen. Today, while instruments intended for use in color measurements share many common components, UV-VIS analytical spectrophotometers are designed to optimize their use in chemometric quantitative analysis, which requires very precise spectral position and very narrow bandpass and moderate baseline ast.

In a typical recent survey Report No. Use of a tolerance equation for other than daylight conditions will require visual confirmation of the level of metamerism in accordance with Practice D It is intended to be used as a single-number shade-passing equation.

Visual color and spectrophotometer readings can also be affected by surface texture, molding parameters, processing method, and viewing light sources. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.

The sections on apparatus, calibration standards and methods, and measurement procedures served little purpose in the light of modern color-measurement technology. This is convenient for certain textile sorting applications and for graphical quality control charting.

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Good correlation with the visual judgments may d244 be obtained when the calculations are made with other illuminants. Validating the specifications, value and safety of your raw materials, products and assets.

It is possible to include information on the direction of a small color difference by listing the three instrumentally determined components of the color difference. Approved May 1, That implies that the equations astj misclassify a color difference with a frequency no greater than that of the most experienced visual color matcher. Evaluating how your products and services meet and exceed quality, safety, sustainability and performance standards.

On the other hand, astj differences obtained for the same s2244 evaluated in different color-scale systems are not likely to be identical. Nor is it possible or reasonable to plot groups of colors in terms of the modi? To avoid asmt, color differences among specimens or the associated tolerances should be compared only when they are obtained for the same color-scale system.

The parameters kL, kC, kH, are the parametric factors that can be used to compensate for texture and other specimen presentation effects while kV is used to adjust the size of the tolerance volume for industrial bias.

Each subsequent color scale based on CIE values has 2 6. The X-Rite i7 Colorimeter is highly automated.

While the CIELAB equation has not completely replaced the use of Hunter LH, aH, bH, this older astk is no longer recommended for other than legacy users, and is therefore included in an Appendix axtm historical purposes.

Lightness L99 5 Hunter Lab and XYZ are standard three dimensional color spaces that allows a precise definition of the color of a test sample.

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