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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Your comments d2244 invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. A color difference equation quanti? The sections on apparatus, calibration standards and methods, and measurement procedures served little purpose in the light of modern color-measurement technology.
Need help or have a question? Evaluating how your products and services meet and exceed quality, safety, sustainability and performance standards.
Astk 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. Those conditions are given in Table 1. An alternative method has been proposed 14 that corrects both problems: Precision and Bias Because of the many trigonometric functions and power functions involved in computing the color space parameters, all computations should be carried out in IEEE?
There is no simple factor that can be ashm to convert accurately color differences or color tolerances in one system to difference or tolerance units in another system for all colors of specimens. 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. 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.
Visually, there is no change in the magnitude of the difference between the specimens simply by switching roles. The procedures for computing the DIN99 formula are: Typically a 50 mm 2″ or mm 4″ disk Data: Color-difference units are computed, from these color-scale values, and approximate the perceived color differences between the reference and the test specimen.
Visual color and spectrophotometer readings can also be affected by surface texture, molding parameters, processing method, and viewing light sources. A number in parentheses indicates the year of last reapproval. 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.
Color analysis can be used to match adjacent parts molded from different materials, or to evaluate color change due to outdoor exposure. This standard has been approved for use by agencies of the Department of Defense.
Color Analysis – CIE94 (ASTM E with ASTM D)
Thus computed color differences are based only on the Euclidean distance in the DIN99 space. ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Hunter Lab and XYZ are standard three dimensional color spaces that allows a precise asym of the color of a test sample.
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 stability.
Due to copyright restrictions, we are not able to provide copies of standards. There should not be a need to break the equation down into perceptual components—the CIELAB components of the model do that already. 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?
Testing Evaluating how your products and services meet and exceed quality, safety, sustainability and performance standards. The equations derived and documented in standard DIN provides an axes rotation and the logarithmic expansion of the new axes to match that of the spacing of the CIE94 color tolerance formula without the need to make the specimen identi?
Color Analysis – CIE94 (ASTM E1347 with ASTM D2244)
Each material and condition of use may require specific color tolerances because other appearance factors, for example, specimen proximity, gloss, and texturemay affect the correlation between the magnitude of a measured color difference and its commercial acceptability. 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 in x, y, and Y.
Enabling astj to identify and mitigate the intrinsic risk in your operations, supply chains and business processes.
Link to Active This link will always route to the current Active version of the standard. Users of this standard are expressly advised that determination of the validity of atsm such patent rights, and the risk of infringement of such rights, are entirely d224 own responsibility. 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.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Specular component included for asym measurements.
The four more recently de? If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Astj on Standards, at the address shown below. 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.
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. Historical Version s – view previous versions of standard. 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.
All the k values default to 1 in the absence of speci? It is intended to be used adtm a single-number shade-passing equation. The parameters atm, 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.