The color properties of a white or nearly colorless sample are represented by whiteness index (WI) or yellowness index (YI).
APHA color is a color scale sometimes referred to as a "yellowness index" that is used to assess the quality of liquids that are clear to yellowish in color.
Samples are solid plates, films, pellets, powder and fluids.
Capabilities
Standard Practice for Computing the Colors of Objects by Using the CIE System (ASTM E 308 )
Calculating Yellowness and Whiteness Indices from Instrumentally Measured Color Coordinates (ASTM E 313 )
Standard Test Method for Color Determination of Plastic Pellets (ASTM 6290)
YI of plastics (ASTM D 1925 )
Standard Practice for Conditioning Plastics for Testing (ASTM D618)
APHA color via internal colorimetric method. Color scale along Standard Test Method for Color of Clear Liquids (Platinum-Cobalt Scale) (ASTM D1209)
