Solution spectrophotometry in the visible and UV can be used to determine the nature of dyes used to color textiles of archaeological historical importance. The curves obtained are compared with those from solutions of known materials. The method requires dyeings made with known natural dyes from the region of interest. Collections of such materials have been obtained from Peru. The principal red dyes of Peru can be identified by means of a single solution curve. Blue, from indigo, can easily be distinguished from the purple dibromoindigo obtained from marine mollusks. Yellow dyes are more difficult to identify and require, in most cases, curves in > 1 solvent. See also AATA 16-1172.