The function of Saybolt Color is to control manufacturing quality of oil. The color is an important quality characteristic of oil, and is easily for user's observation. Under some conditions, the color may serve as an indication of the degree of refinement. For some oil which the color range is known, if its color is beyond this range, the oil perhaps be contaminated. However, it is not reliable to evaluate the oil quality only based on its color. Therefore, it could not freely identify the oil specifiation by its color.