ASTM D2244 Calculation of Color Tolerances
Standard: ASTM D2244 – Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
Scope: This standard covers the calculation of color tolerances and small color differences between opaque specimens.
Products: Paints, coatings, plastics/polymers, vinyl siding, textiles, and a variety of other materials
Procedure: This testing is conducted using a spectrophotometer. Many modern spectrophotometers are highly automated. The spectrophotometer takes a reading of the test specimen after the illuminant, observer angle, and reference color have been specified.
Default parameters for measurement are typically D65 10° (10° Observer, 6500° K, daylight = D65 light), measured in reflection mode with specular included with L*a*b* values.
Result: The color is quantified and reported as an L*a*b* value. The change in color of a specimen after exposure to accelerated weathering is reported as Delta E (or ΔE).