BLACK PIGMENTS FALL INTO THREE CLASSES [1] as described in Table 1. The first two classes derive their color characteristics from the element carbon, the third class from ferrous oxide, Fe³O⁴. Class 1 blacks are carbon blacks that are composed of 90 % or more elemental carbon. Class 2 blacks may be referred to as “carbonaceous pigments” and these contain from 8 % to 88 % elemental carbon.