Volume 13, Number 3, Sept 1991, p.21

The Laboratory for Historical Colorants at UCLA

by David McJunkin, with Catherine McLean and Elizabeth C. Welsh

A tenth century Paracas coca pouch; a parasitic, sap-sucking insect from Armenia; a fourth-century BC Greek statue; a swamp tree of Tabasco; the coronation mantle of the Holy Roman Emperor; a trod-upon weed of the Mexican highlands; the Star Spangled Banner from Ft. McHenry; a synthetic, organic compound invented in 1862: what do these things have in common? They have all been subjects of study in the Laboratory for Historical Colorants housed in the Institute of Geophysics and Planetary Physics at UCLA.

Spurred by a career-long interest in how people make things colorful with organic substances, the laboratory was established in 1974 by Max Saltzman after he retired from work as an industrial chemist of colorants. With the cooperation of a colleague, Professor Rainer Berger, Director of the UCLA Radiocarbon Laboratory, Saltzman set up the Laboratory for Historical Colorants at UCLA. Since then, several thousand analyses have been made of reference material and of unknowns from a wide variety of contexts. In 1978 David McJunkin, with a background in radiocarbon dating and botany, joined the lab.

Saltzman's involvement with research in historic colorants began much earlier. In 1961, Junius Bird, of the American Museum of Natural History, approached Allied Chemical Corporation with the query of whether or not it was possible to identify shellfish purple in an ancient Peruvian textile. This question was shunted around the country until it came to rest in the lap of the chief trouble-shooter of peculiar and arcane questions. Max Saltzman's response was that if Professor Bird could provide an authentic sample of shellfish purple, then he could determine whether or not a particular ancient sample had been dyed with shellfish purple. Over the years, more of these archaeological and historical problems of dye identification were directed to Saltzman.

The first major project that the Laboratory for Historical Colorants undertook was again Andean. A botanist was contracted to make a six-months' survey and collection of the contemporary dye plants of Peru. Controlled dyeings were made, and this collection has served as a definitive reference for identifying ancient Peruvian dyes. Over the years, dye studies of pre- Columbian Andean textiles have been made in collaboration with many institutions and individual scholars including the Los Angeles County Museum of Art, the Field Museum, the Textile Museum, and the Detroit Institute of Arts.

Colorants from other geographic areas have been researched, too. Historic and ethnographic colorants on textiles have been analyzed for the Museum of International Folk Art, the Kunsthistoricshe Museum in Vienna, the School of American Research in Santa Fe, the Natural History Museum of Los Angeles County, the Museum of the American Indian, the Asian Arts Museum, as well as for private collectors and dealers.

Scientific studies of artifacts and artists' materials have been part of professional conservation work in the United States since modern conservation's founding in the 1920s and 1930s. Knowing the identity of a colorant in an artifact enables a conservator to illuminate, store and clean it appropriately. Beyond that, colorant identification helps address numerous questions about provenience, date, method of manufacture, social and economic significance, exchange systems, and other aspects of an artifact's place in society. Citing the colorant used on an artifact should not done by guesswork. Attempts at colorant identification by purely visual means are accurate only by chance.

The requirements for positive identification are: a rigorously vouchered reference collection, a functional technique, a competent practitioner, a sample, and a sufficient desire to know. While there are a variety of useful analytical methods for studying dyes, solution spectrophotometry is preferred at the Laboratory for Historical Colorants for a variety of reasons. Two practical reasons are that it permits double-blind analyses and that it leaves graphic evidence of the results for interpretation. Currently the UCLA laboratory is using the Getty Varian DMS 200 recording spectrophotometer which is serviceable in most applications.

The laboratory continues to be interested in collaborating and cooperating with anyone who has questions about organic colorants. In contrast to the identification of inorganic substances, organic compounds (such as animal and plant-based colorants) are often difficult to identify and necessitate the use of a larger sample. The sample size depends upon the questions to be answered and certain qualities of the colorant. The cost of having analysis done at the Laboratory of Historical Colorants is based on covering the costs or the work. Non-profit institutions are charged a lower fee than commercial enterprises and collectors.

Special research areas at the laboratory include the application of stable, light isotope measurements to the analysis of dyes, distinguishing different botanical sources of indigo, chemotaxonomy of members of the madder family, the analysis of early synthetic dyes, and the natural history of dye woods.

The laboratory welcomes inquiries about the identification of samples. David McJunkin can be called at 213/825-0809 or written at the Laboratory for Historical Colorants, Institute of Geophysics & Planetary Physics, UCLA, Los Angeles, CA 90024. Max Saltzman can be telephoned at 213/476-6711.

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