Nobuko Shibayama

ABSTRACT Madder has been used as a textile dye and pigment in works of art since antiquity. Madder dyes from different botanical species are characterized by different series of anthraquinone derivatives. The occurrence of one or more of these compounds in various relative amounts may provide a useful indication of the plant species used to obtain the dye. In this work, surface-enhanced Raman spectroscopy (SERS) was applied to the analysis of textile fibers dyed with madder from two different botanical species, Oldenlandia umbellata L. and Rubia tinctorum L. The resulting SERS spectra were interpreted in light of the actual composition of the madder dyes as determined by high-performance liquid chromatography. Interestingly, the SERS spectra were found to exhibit very distinctive spectral features depending on the different anthraquinone derivatives present in the dyes. In particular, the SERS spectrum of O. umbellata L. was found to match the spectrum of alizarin, while the SERS spectrum of R. tinctorum L. was surprisingly dominated by signals due to the less studied anthraquinone compound pseudopurpurin. With this study, we demonstrate that SERS spectra may offer valuable information regarding the major coloring constituents present in different madder species. Moreover, our work shows that not only can SERS be used successfully to differentiate among closely related anthraquinone derivatives, but also that this technique is particularly suitable for the detection of pseudopurpurin, leading to the identification of this compound in a number of works of art. Copyright © 2015 John Wiley & Sons, Ltd.

Surface-enhanced Raman scattering (SERS) has found increasing acceptance in art conservation and forensic science for its great potential in detecting trace amounts of material. However, SERS is not a separation technique and, therefore, it is not suitable for distinguishing different components in a mixture. Coupling of thin layer chromatography (TLC) and SERS has been investigated here as a tool for the separation and identification of four alkaloids, namely harmalol, harmaline, harmane and harmine, from the seed extract of Peganum harmala. These compounds were historically used as a dye and for medicinal purposes, and have recently drawn attention due to their antitumor activity. The use of TLC over high-performance liquid chromatography (HPLC) is a convenient way to reduce the amount of material, sophisticated equipment and time needed for the analysis, and coupling of TLC with SERS allows to gain vibrational information on each compound in the mixture. Complementary HPLC analys...

ABSTRACT A paint box and palette that belonged to the American painter James McNeill Whistler(1834-1903) are in the Library of Congress, Washington, DC. There are 37 tubes of paint in the box, including 6 in a separate cardboard box labeled Spectrum Colors. There are also painting and etching tools. The tubes were supplied by five British colormen except for the Spectrum Colors, which came from the American firm of Devoe & Raynolds Inc. Some of the tube labels are missing or illegible. The pigments were identified using polarized light microscopy, X-ray powder diffraction, high performance liquid chromatography, and Raman spectroscopy. Information from Devoe & Raynold's catalogs suggests that the Spectrum Colors were not available before 1909; toluidine red, found in one Spectrum Color, was first synthesized in1904. Thus, the Spectrum Colors must have been put in the paint box after Whistler's death. Of the other pigments in the box, three – graphite, emerald green and synthetic malachite – are not known to have been used by him, but it may be that they are yet to be identified. The paint box was given to the Library of Congress by Joseph and Elizabeth Pennell in 1917, 14 years after the artist's death, and it is not known whether the paint box was used during that time.

... Methanolic extracts (5 mg/ml) were prepared of Dammar (AJ van der Linde, Amsterdam, The Netherlands) and Mastic (H. Schmincke, Erkrath, Germany). ... The aged mastic varnish was removed from the painting “Supper at Emmaus” by Jan Steen (Rijksmuseum, inv. No. ...

Remedial conservation was undertaken on a rare painted silk banner, dated c.1900. The painted decoration consists of a combination of oil gilding and oil paint. The banner was very weak and had stitched and adhered repairs: the underside had extensive flour paste adhesive residues and cellulose nitrate deposits, arising from adhered patches. Removal of the flour paste residues was necessary