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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Typically a 50 mm 2″ or mm 4″ disk Data: 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.
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. ASTM International takes no position respecting the validity of any patent asstm asserted in connection with any item mentioned in this standard.
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.
Thus the equation is highly optimized for pairwise comparison of a product standard to a production test specimen but not for statistical process control. Thus computed color differences are based only on the Euclidean distance in the DIN99 space.
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. Due to copyright restrictions, we are not able astk provide copies of standards. Current edition approved May 1, Inspection Validating the specifications, value and safety of your raw materials, products and assets.
The sections on apparatus, calibration standards and methods, and measurement procedures served little purpose in the light of modern color-measurement technology. Specular component included for integrating-sphere measurements. It was derived xstm from visual observations of automotive paints on steel panels. Historical Version s – view previous versions of standard. Examples of Ka and Kb are tabulated in Table X1. Certification Formally confirming that your products and asym meet all trusted external and internal standards.
This is contrary to what is observed. The four color space terms are computed as follows: Global Reach Intertek is the industry leader with over 42, people in 1, locations in over countries. Those conditions are given in Table 1. After specifying the illuminant, observer angle, and the reference color, the test sample is inserted into the specimen holder and the v2244 takes the reading. Use of a tolerance equation for other than daylight conditions will require visual con?
They are, therefore, included in Appendix X1 for historical purposes and use. Consequently, color differences are seldom if ever computed directly from differences in x, y, and Y. The revision published in omitted these sections, and limited the color spaces and color-difference equations considered, to the three most widely used in the paint and related coatings industry.
Because of the many trigonometric functions and power functions involved in computing the color space parameters, all computations should be carried out in IEEE? Inter-changing the reference and test specimens does not change either the perceived or predicted color differences.
Summary of Practice 4. There should not be a need to break the equation down into perceptual components—the CIELAB components of the model do that already.
Last previous edition approved in as D — Formally confirming that your products and services meet all trusted external and internal standards. Visually, there is no change in the magnitude of the difference between the specimens simply by switching roles. Where it is suspected that the specimens may be metameric, that is, possess different spectral curves though visually alike in color, Practice D should be used to verify instrumental results.
Color Analysis – CIE94 (ASTM E with ASTM D)
The three ashm 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. The CIELAB metric, with its associated color-difference equation, has found wide acceptance in the coatings, plastics, textiles and related industries.
Aastm 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. Use of a tolerance equation for other than daylight conditions will require visual confirmation of the level of metamerism in accordance with Practice D Originally approved in That implies that the equations themselves misclassify a color difference with a frequency no greater than that of the most experienced visual ast, matcher.
Lightness L99 5 Link to Active This link will always route to the current Active version of the standard. Additionally, the colorimetric spectrometer may also be able to report the underlying spectral data from which the colorimetric data were derived. The procedures for computing the DIN99 formula are: On the other hand, color differences obtained for the same specimens evaluated in different color-scale systems are not likely to be identical.
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 colors of specimens. Each material and condition of use may require speci?