Also called mars yellow, this colour is from the pigment group, synthetic iron oxides, which also includes mars black, red oxide and violet oxide. These pigments are derived from the oxidation of metallic iron. Some paint manufacturers label paint made with this synthetic iron oxide pigment “yellow ochre”, though ochre is actually a naturally occurring mineral pigment that is similar in colour. This is an important colour for the artist when altering bright yellows to make them duller. Yellow oxide is an opaque pigment with excellent lightfastness, dull colour, and fairly low tint strength. For certain applications, its cousin transparent yellow oxide is a better choice such as when opacity is not desirable, as in glazing.