Dyes of a Shadow Theatre: Investigating Tholu Bommalu Indian Puppets through a Highly Sensitive Multi-Spectroscopic Approach

Abstract

Tholu Bommalu are typical leather puppets of the traditional Indian shadow theatre. Two of these objects are part of a collection in the International Puppets Museum “Antonio Pasqualino” (Palermo, Sicily, Italy), which can count on one hundred-seventy-three of artifacts. These Indian puppets were investigated to obtain information related to the use of dyes for their manufacturing through a multi-technical approach exploiting the combination of highly sensitive spectroscopic techniques. Wet cotton stubbons were used to entrap small particles of dyes on the fibers from the art objects for the consequent analyses. Visible Light Micro-Reflectance spectroscopy was employed for the preliminary identification of the molecular class of dyes directly on the swabs, while Surface Enhanced Raman Scattering allowed the identification of the specific dye. Several synthetic dyes belonging to different typologies of coloring compounds were identified. The study resulted in an interesting overview of dyes used in recent Tholu Bommalata manufacturing through the combination of micro-invasive techniques directly on the sampling substrate.

Colour Analysis: An Introduction to the Power of Studying Pigments and Dyes in Archaeological and Historical Objects

“…Modern synthetic dyes are discussed in Ciccola et al's contribution [12], which reports on an interesting case study focusing on the analysis of two Indian leather puppets made in the 1970s. The spectroscopic analysis by reflectance spectroscopy and surface enhanced Raman spectroscopy (SERS) led to the identification of malachite green dye, crystal/methyl violet, rhodamine B and eosin Y, although some azo dyes and some complex mixtures were also present but difficult to disclose using only a spectroscopic approach.…”

The 20th century and its new colours: Investigating the molecular structures of historical synthetic dyes using Raman spectroscopy

“…[6][7][8][9] However, more modern synthetically dyed objects are less well-studied. Interest in the identification of synthetic dyes is growing significantly as early synthetically dyed objects are recategorised from contemporary to historical, 10,11 authentication questions arise, 12 and conservation issues begin to require attention. 13 Traditionally and most commonly, textile dyes on fibres are analysed by extraction and separation of components using chromatography with either mass spectrometry [14][15][16][17][18] and/or photodiode array detection.…”

“…Previous Raman studies of synthetic dyes have usually followed the same aforementioned methodologies used for natural dye identifications, 10,50,51 but their chemical situations are quite different. The molecular uniformity of a single dye created in a controlled laboratory environment is likely to be much greater than one, which depends on the natural matrix.…”

“…However, more modern synthetically dyed objects are less well‐studied. Interest in the identification of synthetic dyes is growing significantly as early synthetically dyed objects are re‐categorised from contemporary to historical, 10,11 authentication questions arise, 12 and conservation issues begin to require attention 13 …”

New Advances in Dye Analyses: In Situ Gel-Supported Liquid Extraction from Paint Layers and Textiles for SERS and HPLC-MS/MS Identification

“…Because of their strong fluorescence, dyes are not suited for Raman spectroscopy identification. However, fluorescence can be quenched when signals are enhanced by means of metal nanoparticles (NPs), and very good dye spectra can be obtained by means of surface enhanced Raman spectroscopy (SERS) [ 6 , 7 , 8 , 9 , 10 ]. Nonetheless, the phenomenon occurs when the analyte interacts with metal NPs, which cannot be applied directly on the artifact and, thus, micro sampling is required anyways [ 6 , 11 ].…”