2 EXPERIMENTAL

MATERIALS AND METHODS.4 Cochineal dyed wool samples were obtained from the Textile Conservation Dept., Metropolitan Museum of Art, New York. These samples were produced in a collaborative exercise during a 5-day workshop conducted by Fred Gerber in September 1978. The samples were stored on ragboard sheets in a bound sample book.

Although details are ambiguous, mordants were applied before dyeing. The following quantities of mordant were used per pound of wool yarn: K2SO4AI2(SO4)3 �24H2O, 4.0 oz; CuSO4 �5H2O, 1.0 oz; FeSO4 �7H2O, 1.0 oz; SnC12 �2H2O, 0.5 oz; K2Cr2O7, 0.5 oz.

Mordants were dissolved in sufficient quantities of water to insure solution of mordants, heated, and the wool yarn was then added to the mordant solution. The yarn was left in the solution for some time depending on the mordants. Dried cochineal insect grains from the Canary Islands were mashed and added to warm water. After the dye was extracted into the water larger dye baths were prepared and the mordanted yarn was added and simmered (90–100�C) ca. 1 h. Different dye baths were used for each mordant. The dyed yarns were then rinsed in cold tap water and dried. Some of the mordant/dye solutions contained unspecified amounts of additives other than metallic mordants: cream of tartar, oxalic acid, sumac. The cochineal and the sumac were not purified or refined products but used as received. The sumac was field collected on the morning of use.

ANALYSES. The samples were prepared for scanning electron microscopy and examined in an AMRay 1600T with attached Kevex X-ray spectrometer system. Details of the treatment for analysis and the equipment used has been described previously.1 In addition, elemental dot mapping and photomicrography were performed on the samples. For atmoic absorption analysis (AA), samples were submitted to Schwartzkopf Microanalytical Lab, Woodside, NY 11377.