Developing New Methods for Recoloring Faded Taxidermy
The initial sample set undergoing accelerated aging in our Q-SUN chamber is expected to be the largest. It includes all of the Orasol dyes that we have been able to acquire to date from the manufacturer BASF and retail supplier Kremer Pigments, as well as Sorasolve dyes available from Museum Services Corporation (MSC). This post includes a listing of all of our dye samples. For a comprehensive concordance of materials by manufacturer, current and former product names, and Colour Index Generic Names (CIGN), please see the table at the end of the post.
BASF does not sell small quantities of its product directly to consumers, but samples may be requested from the company for testing purposes. Materials obtained this way are understood to be of relatively recent production.
Orasol dyes, manufactured by BASF, and available from Kremer Pigments
Kremer sells small quantities of BASF Orasol dyes retail. To do so, they purchase dyes in bulk from BASF and warehouse the stock until it is sold. As a result, dyes purchased from Kremer have an unknown production and storage history. Orasol products listed in Kremer’s product catalog are identified using both old and newer Orasol naming systems, reflecting the name in use by the manufacturer at the time Kremer made its purchase from BASF.
Sorasolve dyes, manufactured/supplied by First Source Worldwide LLC, and available from Museum Services Corporation (MSC)
Museum Service Corporation’s retail product-catalog lists their metal-complex solvent dyes using the old BASF naming system for the Orasol® brand; however, the dyes are supplied to MSC under the brand name Sorasolve by First Source Worldwide LLC, an American chemical company based in Neenah, Wisconsin. Orasol® and Sorasolve dyes with the same Colour Index Generic Name share an essential colorant with the same chemical constitution.
We have characterized all of these dyes using fourier transform infrared spectroscopy (FTIR). Our results confirm that samples of old and new Orasol® dyes, as well as the related Sorasolve dyes, have very similar infrared spectra (see image below).
All of these dyes are soluble in a wide selection of solvents. As mentioned previously, during dye testing conducted in conjunction with the renovation of the dioramas in the Jill and Lewis Bernard Family Hall of North American Mammals, we observed that solvent choice can have subtle effects on both the color and lightfastness of the dyes. In order to explore these effects more extensively, five different solvents were selected for our present tests. They reflect a range of properties with respect to dye solubility and volatility/evaporation rate. Among them are solvents commonly used in the conservation of art and artifacts, as well as some others used in previous testing by Ciba-Geigy. Unusually toxic solvents or solvents that present other problems precluding their general use in restoration work were excluded.
The solvents we are testing include: