Spectroscopic investigation of modern pigments on purportedly medieval miniatures by the ‘Spanish Forger’

Abstract

Five miniatures by the so-called 'Spanish Forger' were acquired by the Victoria and Albert Museum in 2008. Believed to be authentic medieval miniatures until the mid-twentieth century, they are now considered to have been painted around the end of the nineteenth and the beginning of the twentieth century. To investigate this attribution and to gather detailed knowledge about the materials used by the artist, a comprehensive pigment analysis by Raman microscopy and X-ray fluorescence was carried out. Although traditional materials such as vermilion, carbon black, red lead, lead white and indigo were identified, many others (chrome yellow, Scheele's green, emerald green and ultramarine blue) are modern and synthetic pigments, a result which provides a firm scientific basis for stating that the miniatures are forgeries.

Raman microscopy and x-ray fluorescence analysis of pigments on medieval and Renaissance Italian manuscript cuttings

“…It can also aid in the identification of previous restorations and in the detection of forgeries (18). Further, x-ray fluorescence (XRF) spectroscopy has also been used, this having previously been shown to be very effective for the identification of gold, silver and bismuth in illuminations (19 and 20).…”

Testing of Raman spectroscopy as a non‐invasive tool for the investigation of glass‐protected pastels

“…In the pastels analysed, the greens are always obtained mixing different pigments; this has been demonstrated to occur also in glass, ceramics [7,16,24,25] and pigmented wallpapers or medieval miniatures, [9,26,27] because of the low stability and/or high corrosivity, as in the case of verdigris, [3,28] of the available green pigments. In this case, it can always be recognized as chrome yellow, to which Prussian blue and carbon black or white pigments can be added according to the desired hue (Tables 2-4).…”

Forgery detection on an Arabic illuminated manuscript by micro‐Raman and X‐ray fluorescence spectroscopy

“…Zinc white is a particularly difficult pigment to detect by Raman spectroscopy as it is highly fluorescent, [24] but in our case it was possible thanks to its Raman bands at 433 and 377 cm −1 (Fig. 3(b)).…”

“…This pigment was traditionally employed on medieval manuscripts. [24] Both vermilion from mining sources (also called cinnabar) and from artificial production were used; however, neither XRF nor Raman spectroscopy allows making a distinction between the natural and synthetic variants. [21] Titanium, zinc and barium were detected by XRF in the red and also in the black letters (not labelled, Fig.…”

“…[24] Goethite is the chromophore of all yellow natural pigments, and hematite that of the red ones. [28] Green and blue synthetic organic pigments Copper (Fig.…”