Zinc Chromate. This [pigment] is made either from zinc salts and bichromate of potash or zinc oxide heated with chrome salts, frequently in the presence of acid. Like the rest of the chromate pigments, it is a very slow-drying material, often requiring over a week to set up, unless considerable drier is added. In spite of the impurities which it carries, it has shown itself to be one of the most inhibitive pigments known and has demonstrated its value in even small percentages in paints for iron and steel. It dries to a hard adherent film that tends to protect metal from corrosion.
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| Indian Red | Metallic Brown |
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| Basic Lead Chromate (American Vermilion) | Red Lead |
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| Paranitraniline | Chrome Yellow |
Prussian Blue. On oxidizing the precipitate resulting from the interaction of solutions of prussiate of potash and copperas (iron sulphate), Prussian blue as used in the paint trade is prepared. It has a specific gravity of 1.9. The pigment shows an amorphous structure, the [particles] varying greatly in size.
Ultramarine Blue. This bright blue pigment is prepared by burning silica, china clay, soda ash and sulphur in pots or furnaces. It has a specific gravity of 2.4. It is of little value as a paint pigment on account of its sulphur content, which causes darkening when mixed with lead pigments, and corrosion when applied to iron or steel. The darkness of the [photograph] is due to the massing of the pigment particles.
Chrome Green. Chrome green is prepared as a paint pigment from nitrate of lead, Chinese blue, and bichromate of soda. It has a gravity of 4 and is liable to contain slight traces of lead salts. The [particles] when magnified appear very fine and flocculent. This color is often precipitated on pigments, such as barytes, which do not reduce its tone.
Bone Black. By grinding the carbonaceous matter resulting from the charring of bones, in iron retorts, the pigment bone black is prepared. It contains about 15% of carbon and 85% of calcium phosphate. It has a gravity of 2.7. Comparatively large [particles] of charred bone can be seen scattered throughout the mass, resulting from the difficulty of grinding to a uniform size.
Carbon Black. This form of very pure carbon results from the combustion of gas. Its gravity, 1.09, is lower than that of lampblack, which shows a gravity of 1.8. It is used in much the same way and for the same purposes as lampblack. In [physical appearance] it shows great similarity to the particles of lampblack.
Lampblack. This pigment, made from the combustion of oils, consists very often of more than 99% carbon. It has wonderful tinting value. The [particles] show a fine, fibrous structure with a tendency toward agglomeration. They differ greatly in physical appearance from those of either graphite or bone black, being exceedingly more uniform than the latter.