Inorganic pigments color compounding

The term FD C color, often seen on ingredients labels, refers to food, drug, and cosmetic colors. These are organic compounds (as opposed to inorganic pigments, such as titanium dioxide) that are so intense in color that it takes only very tiny amounts to color something, and thus they can be used in concentrations so minute that they are safe for consumption. 

Some inorganic compounds are used as food additives and food colorants. They include titanium dioxide, carbon black, iron oxides, ultramarin, and calcium carbonate. Some of them are important for properties other than the ability to impart color. Titanium is the most commonly used inorganic pigment in food and will be briefly discussed below. ° "°... 

Inorganic pigments are found in the earth. Iron and lead oxides provide earth colors. Copper calcium silicate and cobalt stannate provide blues. The colors burnt sienna and burnt umber come from iron oxides. Green pigments come from chromic oxide, calcinated cobalt, and zinc and aluminum oxides. Red pigments come from cadmium sulfide, cadmium selenide, and barium sulfate. All these chemical compounds come from the earth. 

CdS is used in the semiconductor industry (Bruce and O Hare 1996), and also extensively as a pigment. The available pigment colors are mostly yellow, orange, red to Bordeaux red as (Hg,Cd)S and Cd(S,Se), and are used in polystyrene, polyethene, polypro-pene, and polycarbonate. The pigments belong to the most brilliant inorganic compounds and are prepared from either Cd metal or metal salts they are insoluble in water (Bucher et al. 1984). Other important uses of Cd include plating (Cd-coated steel), batteries, and in polyvinyl chloride (as a stabilizer, especially in outdoor window frames). 

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