Clothlet colors were used in medieval manuscript illumination. Medieval descriptions for the use of clothlet colors are given. The major source for clothlet colors was turnsole (<i>Chrozophora tinctoria</i> Juss.). Problems in identifying this turnsole plant and its colorant are discussed. Application of absorption, fluorescence emission, and three-dimensional fluorescence spectromentry in identifying turnsole clothlet colors is described. It is possible to distinguish turnsole colorants from other organic colorants in clothlets.