The Dye Is Cast

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.

Orasol dyes, manufactured by and available from BASF

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® Red 330 (CIGN Solvent Red 130)
  • Orasol® Red 335 (CIGN Solvent Red 122)
  • Orasol® Red 355 (CIGN Solvent Red 119)
  • Orasol® Red 363 (CIGN Solvent Red 125)
  • Orasol® Red 365 (CIGN Solvent Red 160)
  • Orasol® Red 395 (CIGN Solvent Red 122)
  • Orasol® Red 471 (CIGN Solvent Red 118)
  • Orasol® Pink 478 (CIGN Solvent Red 127)
  • Orasol® Orange 245 (CIGN Solvent Orange 56)
  • Orasol® Orange 247 (CIGN Solvent Orange 11)
  • Orasol® Orange 251 (CIGN Solvent Orange 54)
  • Orasol® Orange 272 (CIGN Solvent Orange 99)
  • Orasol® Yellow 081 (CIGN Solvent Yellow 79)
  • Orasol® Yellow 141 (CIGN Solvent Yellow 81)
  • Orasol® Yellow 152 (CIGN Solvent Yellow 88)
  • Orasol® Yellow 157 (CIGN Solvent Yellow 82)
  • Orasol® Yellow 190 (CIGN Solvent Yellow 89)
  • Orasol® Blue 825 (CIGN Solvent Blue 67)
  • Orasol® Blue 855 (CIGN Solvent Blue 70)
  • Orasol® Brown 324 (CIGN Solvent Brown 43)
  • Orasol® Brown 326 (CIGN Solvent Brown 44)
  • Orasol® Black X45 (CIGN Solvent Black 28)
  • Orasol® Black X51 (CIGN Solvent Black 27)
  • Orasol® Black X55 (CIGN Solvent Black 29)

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.

  • Orasol® Red 395 (CIGN Solvent Red 122)
  • Orasol® Orange 247 (CIGN Solvent Orange 11)
  • Orasol® Yellow 152 (CIGN Solvent Yellow 88)
  • Orasol® Yellow 4GN (CIGN Solvent Yellow 146)
  • Orasol® Yellow 2RLN (CIGN Solvent Yellow 89)
  • Orasol® Blue 825 (CIGN Solvent Blue 67)
  • Orasol® Brown 324 (CIGN Solvent Brown 43)

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.

  • Yellow 2RLN (Sorasolve/CIGN Solvent Yellow 89)
  • Yellow 4GN (Sorasolve/CIGN Solvent Yellow 146)
  • Yellow 2GLN (Sorasolve/CIGN Solvent Yellow 88)
  • Orange G (Sorasolve/CIGN Solvent Orange 11)
  • Red BL (Sorasolve/CIGN Solvent Red 122)
  • Red G (Sorasolve/CIGN Solvent Red 125)
  • Pink 5BLG (Sorasolve/CIGN Solvent Red 127)
  • Blue GN (Sorasolve/CIGN Solvent Blue 67)
  • Brown 2GL (Sorasolve/CIGN Solvent Brown 42)
  • Brown 2RL (Sorasolve/CIGN Solvent Brown 43)
  • Brown 6RL (Sorasolve/CIGN Solvent Brown 44)
  • Black CN (Sorasolve/CIGN Solvent Black 28)
  • Black RLI (Sorasolve/CIGN Solvent Black 29)

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).

Yellow 89

FTIR spectra for Solvent Yellow 89 samples acquired from BASF (purple line), Kremer (blue line), and MSC (red line). Note the likeness between spectra, indicating that the three dyes sold by three companies under the same CIGN are chemically very similar, if not the same.

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:

  • Acetone
  • Ethyl acetate
  • Ethanol
  • Isopropanol
  • Propylene glycol monomethyl ether (PGME).
acetone_PGME

Dye sample Red BL (CIGN Solvent Red 122) purchased from Kremer. Note the difference the solvent choice makes in surface texture/coverage between the sample dissolved in acetone (left) and the same sample dissolved in PGME (right). AMNH/F. Ritchie

Dye concordance table

Concordance of dye materials by current and former product names, Colour Index Generic Names (CIGN), chemical composition, and source.

 

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2 thoughts on “The Dye Is Cast

  1. Pingback: Dyed Fur Samples: Part 1 | In Their True Colors
  2. Pingback: Color by the Numbers, Part 1: Spectrophotometry vs. Colorimetry | In Their True Colors

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