ORGANIC YELLOWS

Manuscript painters had two other sources of bright organic yellows like saffron: buckthorn and weld. Weld pigments were used to some extent by panel painters, and buckthorn was reserved exclusively for books. There were largely excluded from the palettes of other painters because of their lack of durability.

ORPIMENT

Orpiment is a sulphide of arsenic, found in nature as a stone, a golden hued yellow that was used by painters of books in the middle ages. Chiefly imported into Europe from Asia Minor, it was this resemblance to gold that tantalized the ancients and medieval alchemists. Pliny reports that a prince named Caius had an enormous quantity of it cooked up to extract the gold, making an excellent gold which was however, too light in weight. Painters used it only as a paint, and not as a precious metal, and was used especially for writing in imitation of gold. Its color is a light, vivid yellow, sometimes pure yellow but often inclined toward orange. In its natural state, it has a mica-like sparkle which recalls the luster of metallic gold. Orpiment was not compatible for other colors, and could not be used to modify green tones containing verdigris, as the sulphur of the orpiment attacked the copper; and for the same reason was not compatible with lead white. It also had a corrosive action on binding materials, and has quite often decayed and come away from panels and parchment. During the late Middle ages they gladly turned to substitutes, though it was not completely abandoned until the end of the nineteenth century. When mixed with zinc or titanium white, it loses its yellow tones becoming a pale brown/beige.