YELLOW OCHRES

Earth colors which owe their hues to the iron hydroxide that they contain. Many painters are firmly convinced that there is no better earth or natural color, yet they are impure, often with admixtures of humus or bituminous organic matter, or clay, etc. For panels and walls in medieval painting they were widely used though substandard at times; it was the opacity of the product they was so admired. The beauty of these colors are due to such impurities, and if washed often lose their color, even though this washing is necessary to freeing them from harmful iron sulphate compounds. It was so common a product in the middle ages that they left no recipes for preparation as I suppose this was a given to all painters. Ochre colors are found everywhere in nature, the purest coming from France, but additionally from the Harz mountains and upper Palatinate. An "Amberg Yellow" from these areas was prized for fresco painting, but is no longer available.

Ochres are ground and washed. Old masters worked hard in preparing them, often doing this procedure themselves. They were distinguished by the degree of brightness: light ochre, medium ochre, gold ochre, dark ochre, Italian earth, Roman ochre, brown ochre, etc. Gray varieties such as stone ochre and greenish ochre are best avoided. The have a medium covering power and must be pure. Because of their clay content they are apt to decompose, having a bad effect on the superimposed coats of varnish, and also require 60% oil, but again, permanent when free of impurities, and useful in all techniques. On badly preserved paintings, the ochre can be wiped off like dust however, and if impure, will turn brown and later dark as the impurities are soluble in oil. The artificial varieties have the advantage of being reliable in color and purity, which is not the case in the natural product, and are known as Mars yellow. According to Maximillian Toch (1940s), there are many varieties of American yellow ochre which are primarily found in Georgia and Pennsylvania. The Ochres found in the rest of the States are not good enough to be used as pigments. The two formerly mentioned however, are some as strong as the French ochres, but "their shade is not quite as clear". I am unsure if this refers to inequities from batch to batch, or within the pigment itself.

YELLOW: GENERAL NOTES

Most important yellow in medieval painting is the metal gold. Yellow played an important role however in terms of their techniques, and most often, as the imitation of gold, along with modification of greens and to a lesser extent, reds. Perhaps the least important use was that of the representation of yellow things. Nothing disturbs the balance of decorative painting more than large areas of strong yellow as they tend to be obvious and conspicuous, most of all in glass painting, where they add nothing to the interiors they illuminate. This wariness followed through to all forms of medieval painting therefore, admiring the golden, but abhorring the bilious. The greater freedom of yellow is one of the marks of the approach of the Renaissance, when many new forms of yellow pigment were introduced in the course of the fourteenth and fifteenth centuries.