Calcium carbonate is lightfast. Like all carbonates, it reacts with strong acids
copper chromite black
Black Spinel is a very neutral opaque black pigment, excellent for tinting to create neutral grays.
Black Spinel has excellent lightfastness.
Black Spinel is mildly toxic. The pigment itself has an extremely fine particle size. It causes irritation and ulceration to skin. Respiratory exposure and exposure to dust are serious concerns.
Black Spinel is much more expensive than carbon-based blacks. Its use as a pigment has been limited to applications where a truly neutral black or gray tone is needed.
Jet Black, Ebony Black, Neutral Black, Copper Chromite Black.
ZnO + Fe203 + Cr2O3
Zinc Iron Chromite Brown is a dark reddish brown pigment that is opaque and staining.
Zinc Iron Chromite Brown is exceptionally lightfast, heat resistant, weather resistant, and durable.
Zinc Iron Chromite Brown has not been identified as hazardous, but it is likely to contain impurities that are irritating to the skin or lungs. Pigment from natural ores may contain traces of heavy metals.
Because of its exceptional durability and heat resistance, Zinc Iron Chromite is used as a brown pigment in ceramics.
Shepherd Brown 12
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