Color Theory in Medieval Islamic Lapidaries: Nıshābūrı, Tūsı and Kāshānı

Abstract

This paper discusses descriptions of color theory in a series of lapidaries by Nıshābūrı, Tūsı and Kāshānı, written in 1196, ca. 1258 and in 1300, respectively. The texts are almost identical and seem to originate from Nıshābūrı. They describe a color theory that deviates from the Aristotelian account in several ways. They represent one of the first instances in which it is stated explicitly that by mixing black and white, grey is produced. This contradicts the Aristotelian dogma that such mixtures may produce all other colors. The texts are the first to refer explicitly to a hue scale, recognizing that by mixing blue and yellow in different proportions, colors are produced that change gradually from blue, via green, to yellow. Only tonal scales, obtained by mixing a color pigment with black or white, had been described before. In spite of the description of a hue scale in this text and tonal scales in another text by Tūsı, it is shown that the authors of these texts did not yet distinguish between differences in lightness and differences in hue.