The Colour Index assesses the colour of the oil and provides a quick indication of oxidation, contamination or degradation. A darker colour may mean that the oil is aged, has been exposed to high temperatures, or contains soot and particles.
The analysis is done by visual comparison against a color scale, or photometrically by measuring light transmission through the sample.
The customer gets a simple but useful indicator of the overall condition of the oil and can use this as part of a trend analysis to detect deterioration early.