Historical
ASTM E2539-14
Standard Test Method for Multiangle Color Measurement of Interference Pigments
1.1 This test method covers the instrumental requirements and required parameters needed to make instrumental color measurements of thin film interference pigments. This test method is designed to encompass interference pigments used in architectural applications, automobiles, coatings, cosmetics, inks, packaging, paints, plastics, printing, security, and other applications.
1.2 Characterization of the optical behavior of materials colored with interference pigments requires measurement at multiple angles of illumination and detection.
1.3 Data taken utilizing this test method are quantitative and are appropriate for quality control of interference pigment color.
1.4 The measurement results are usually expressed as reflectance factors, tristimulus color values, or as CIE L*a*b* color coordinates and color difference.
1.5 The totality of data taken may not be necessary for evaluating mixtures also containing non-interference pigments. The committee is investigating and evaluating the appropriateness of this test method for those materials. It is the responsibility of the users to determine the applicability of this test method for their specific applications.
1.6 Interference pigments are typically evaluated for color and color appearance in a medium, such as paint or ink. The gonioapparent effect depends strongly on the physical and chemical properties of the medium. Some of the properties affecting color and color appearance include vehicle viscosity, thickness, transparency, and volume solids. As a general rule, for quality control purposes, interference pigments are best evaluated in a masstone product form. In some cases this product form may be the final product form, or more typically a qualified simulation of the intended product form (such as a paint drawdown) that in terms of color and appearance correlates to final product application.
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