Non-invasive characterisation of binding media on painted glass magic lantern plates using mid-infrared fibre-optic reflectance spectroscopy

Painted glass magic lantern plates from the Museo Nazionale del Cinema, Torino (Italy), were studied using mid-infrared (mid-IR) fibre-optic reflectance spectroscopy (FORS), a non-invasive technique, to test its potential for the identification of the types of binding media used in the paints. Gum, oil and resin media were identified on the plates and the amounts of these media varied from place to place; the discovery of these media correlate well with the literature on magic lantern plate preparation and painting. The spectra collected are reported uncorrected and also with the fingerprint region corrected with the Kramers–Kronig correction, which corrects distorted peaks caused by specular reflections.