Meaning of colors: the color of oil, can reflect the degree of purification and stability. Refined base oil, removal of oxides and sulphides in oil clean and lighter in color. But even if refining conditions are the same, different source and category of the crude oil in the production of base oil, its color and transparency might not be the same. After the use of additives in base oils, changes in color, exquisite color used as a fuel level indicator has lost its original meaning. Therefore, most of the oil has no color (or chroma) indicators.