Pigment Blood is a term used to describe the two substances, Heme and OCHRE, which are used to create a variety of colors. Heme is a four-letter word that refers to a type of iron-containing compound found in hemoglobin, the oxygen-carrying protein in red blood cells. OCHRE is a five-letter word that refers to a yellowish-brown earth pigment, which is often used as a natural dye. Both Heme and OCHRE are used to create a range of colors in art, cosmetics, and other products.