The Colour Index assesses the colour of the oil and provides a quick indication of oxidation, contamination or degradation. A darker color may mean that the oil is aged, has been exposed to high temperature, or contains soot and particles.
The analysis is done by visual comparison against a color scale, or photometrically using measurement of light transmission through the sample.
The customer is given 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.