Reliable color control of transparent liquids

The color of transparent liquids is critical as a change can indicate contamination or impurities in the raw material, process variations caused by heating and oxidation, or degradation of products exposed to weathering over time. Visual tests have been established by comparing the sample to a known standard. Today, objective measurements can be done with color spectrophotometers that give reliable data on a consistent basis. Besides degree of yellowness, such spectrophotometers also describe color differences three dimensionally: red/green, yellow/blue and light/dark differences.