The APHA/Platinum-Cobalt color scale is described in ASTM D1209. The ASTM method is an off-line manual laboratory method. The original test design required an observer to compare the color of a product to a known standard, and then judge the “color”. This color scale ranges from 0 to 500. The lowest value of 0 is referred to as water white. A value of 500 is distinctly yellow. (Below illustrates the contrast from 0- 100 range.)
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