Notebook

Notebook, 1993- MATERIALS & METHODS - Pigments

On Quality of Pigments

Pigments are produced in grades that vary in regard to chemical purity, uniformity of particle size, and trueness of color type. Methods of refining, washing, compounding, and grinding colors affect in a material way the tinting strength, film-forming properties, color, and durability of the paint. Thus yellow ocher may be native iron hydroxide in both brand X and brand Y, but one brand may use a pigment that is poorly selected and badly washed and refined. Although both pigments could be correctly labeled genuine yellow ocher, native iron hydroxide, the less carefully processed color might exhibit a muddier tone and age in a disappointing way. In some cases, presence of impurities left in the pigment may make it dangerous to combine it with other colors. Many prohibitions concerning the intermixing of certain colors apply to indifferently made pigments but not to carefully produced, top-quality versions of the same substances. Many colors considered of "borderline" permanence, such as Prussian blue or artificial alizarin crimson, exhibit poor color stability in cheap grades but, if manufactured with great care, are permanent under ordinary conditions. [p. 26]

[Kay, Reed. The Painter's Guide to Studio Methods and Materials. Englewood Cliffs, NJ: Prentice-Hall, Inc., 1983.]

NOTEBOOK | Links

Copyright

The contents of this site, including all images and text, are for personal, educational, non-commercial use only. The contents of this site may not be reproduced in any form without proper reference to Text, Author, Publisher, and Date of Publication [and page #s when suitable].