Gamblin Cadmium Colors are in regular chromatic steps from Cadmium Yellow Light through Cadmium Red Deep. Chemically pure Cadmium Orange is a medium opaque orange. No health labeling required. Pigment: Concentrated cadmium sulfo-selenide (PO 20) Vehicle: Alkali refined linseed oil Lightfastness I, Series 4, OPAQUE, MSDS