ASTM D2129 Test Method for Color of Clear Electrical Insulating Liquids (Platinum-Cobalt Scale)
3. Summary of Test Method
3.1 The color determined by this test method is derived by comparing the color of the test specimen with that of a series of numbered color reference standards using transmitted light under prescribed conditions. The procedure described is based on that for measuring the color of water and clear liquids according to the platinum-cobalt scale. This scale is suitable for measurements over the color range from 5 to 300. The color of test specimens darker than 300 on the platinum-cobalt scale must be measured according to the ASTM Color Scale as described in Test Method D1500. The use of the platinum- cobalt scale in this way is primarily of value as an expansion of the lower part of the ASTM Color Scale, especially in the range between 0 and 1.
4. Significance and Use
4.1 Color is significant chiefly as an indicator of contamination in electrical insulating liquids. Frequently this contamination is the result of solvent action in the apparatus involved or it may indicate possible contamination. No definite relationship can be established between color and the physical and electrical characteristics of the liquid; for that reason color in itself has limited value as a measure of condition. For more precise determination of color. Test Method D1209 may be used.
