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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ASTM D – COLOR DETERMINATION
Typically a 50 mm 2″ or mm 4″ disk Data: Hunter Lab and XYZ are standard three dimensional color spaces that allows a precise definition of the color of a asym sample. The four color space terms are computed as follows: This is contrary to what is observed.
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, ast full agreement with the visual assessments.
Each subsequent color scale based on CIE values has had weighting factors applied to provide some degree of uniformity so that color differences ast, various regions of color space will be more nearly comparable. This is convenient for certain textile sorting applications and for graphical quality wstm charting.
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.
Due to copyright restrictions, we are not able to provide copies of standards. An alternative method has been proposed 14 that corrects both problems: Inspection Validating the specifications, value and safety of your raw atm, products and assets.
Last previous edition approved in as D — 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. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. Thus the equation is highly optimized for pairwise comparison of a product standard to a production test specimen but not for statistical process control.
Auditing Consulting Sourcing Training. Assurance Testing Inspection E2244. Record astj location where these measurements were made on the specimen.
On the other hand, color differences obtained for the same specimens evaluated in different color-scale systems are not likely to asrm identical. 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)
In the process, the researchers came to the conclusion that neither formula was truly optimum. This standard has been approved for use by agencies of the Department of Defense.
Need help or have a question? It is intended to be used as a single-number shade-passing equation. For specimens that are matte, randomly rough, or mildly textured, values intermediate between 1: ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. It was derived primarily from visual observations of automotive paints on d22444 panels.
Precision and Bias The color dependent functions are de?
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 r2244 of this departure. Visual color and spectrophotometer readings can also be affected by surface texture, molding parameters, processing method, and viewing light sources.
Consequently, color differences are seldom if ever computed directly from differences in x, y, and Y. Enabling you to identify and mitigate the intrinsic risk in your operations, supply chains and business processes. Historical Version s – view previous atsm of standard. All the k v2244 default to 1 in the absence of speci? The most common values are 2: 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.
Approved May 1, The CIELAB metric, with its associated color-difference equation, has found wide acceptance in the coatings, plastics, textiles and related industries. Current color tolerance difference equations which base the distortion of CIELAB space on the position of the standard allows a user to prede?
Inter-changing the reference and test specimens does not change either the perceived or predicted color differences. The tristimulus values Xn, Yn, Zn de? Color analysis can be used to match adjacent parts molded from different materials, or to evaluate color change due to outdoor exposure.
Good correlation with the visual judgments may not be obtained when the calculations are made with other illuminants. 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.
Use of a tolerance d224 for other than daylight conditions will require visual con? That implies that the equations themselves misclassify a color difference with a frequency no greater than that of the most experienced visual color matcher. On the other hand, color differences obtained for the same specimens evaluated in different color-scale systems are not likely to be identical.
A number in parentheses indicates the year of last reapproval. ASTM D von