Comparative assessment of two portable Raman spectrometers for the characterisation of historical natural dye lakes

This paper explores the use of portable Raman instruments to characterise natural dye lakes in paint mixtures, as an alternative approach other techniques (e.g. SERS). spectroscopy has indeed been used extensively study dyes pure substances or artistic pigments (dye lakes). However, examination these compounds with is particularly challenging because a strong fluorescence, relatively weak signal and their occurrence at low concentrations artefacts. Because challenges, typical way analysing materials through either surface-enhanced (SERS) Fourier-transform (FT) spectroscopy, yet those approaches are not always desirable art analysis, especially they often require micro-sampling. Therefore, this potential using commercial mobile instruments, which would open possibilities for direct situ analysis. Two dispersive one fibre-optic probe 1064-nm excitation laser subtracted-shifted (SSE) post-processing algorithm, have tested feasibility lakes. spectra were acquired from set laboratory reproductions mixtures prepared chosen common lakes, three red (brazilwood, cochineal madder) yellow (weld), mixed proteinaceous polysaccharide binders. The evaluated, it shown that produce detectable signal, spite interference painting support (parchment) two provide significantly different information.