A FORS (Fiber Optics Reflectance Spectroscopy) database for the re-evalutation of a historic pattern books collection: the case of the Cassella Color Company
The Cassella Color Company was founded at Frankfurt am Main (Germany) by Leopold Cassella in 1789 and started towards the end of the 19th century a dyestuff manufacture, rapidly becoming one of the worldwide major synthetic dyes producers. In particular, the firm specialized in the patenting and production of “Diamine Colors”, azo dyes with the general structure of a diamine (benzidine, tolidine, methoxy tolidine or ethoxy tolidine) linked to two terminal alike or different groups [1]. Their pattern books describe the developing of these dyes and the various dyeing processes of silk, cotton, linen, wool, straw and chips: they contain also fragments of fabrics colored with the synthesized dyes, thoroughly supplied with the description and percentage of each dye, applied individually or in a mixture. The precious collection of the Commodity Science Museum of the University Aldo Moro of Bari (Italy) includes rare pattern books of yarns and textiles dated to the end of the 19th – beginning of the 20th century, among which an important corpus of the Cassella Color Company editions. This work is included in a wider project aimed to the re-evaluation of the Commodity Science Museum collection, starting with the scientific cataloguing by means of reflectance spectroscopy data of the dyestuff production from the above-mentioned firm. Fiber Optics Reflectance Spectroscopy (FORS), much used for the identification of dyes and pigments, has scarcely been employed in the study of textile dyestuff [2], for which the main applications were directed to the revelation of natural/traditional dyes in fabrics prior to the era of synthetic colors [3, 4]. The FORS technique was employed with the aim of generating a reference database for the future characterizations of 20th century dyestuff. Up to now, silk cotton blend, wool cotton blend, straw and chips dyed with Diamine Colors and finally color lakes precipitated in different ways were analyzed
