Micro‐Raman spectroscopic analysis of inks and pigments in illuminated medieval old‐Slavonic manuscripts

Abstract

Micro-Raman spectroscopy was applied in characterisation of inks and pigments used in the text, illuminations and miniatures of two old-Slavonic manuscripts: Vrutok four gospels (13th-14th centuries) and Benche four gospels (16th century). They were written in old-Slavonic language with old Cyrillic alphabet. Both were decorated with ornaments in so called Balkan style characterised with intertwined rings and floral motifs. Only four colours/pigments were used in the simple miniature and ornaments in Vrutok book: orpiment, vermilion, organo-copper complex and mixed ink. Much richer palette of pigments was revealed in the Benche book: calcite, gypsum, lead white, yellow ochre, pararealgar/realgar, vermilion, red lead, red ocra, organo-copper complex, malachite, indigo, iron gall ink, carbon black and pure metallic gold. The use of pigments in ornaments compared with miniatures is somewhat different in Benche book, suggesting that either handwriting and ornamenting on one side and miniatures, on the other, were done by different persons/painters or depiction of sacral themes of the miniatures canonically required the use of more expensive/elaborate pigments.Micro-Raman spectroscopy allowed in situ, non-destructive, rapid and unambiguous identification of the majority of pigments used in the text, ornamentations and miniatures in the Vrutok and Benche four gospels. In case of uncertainty in identification of pigments, scanning electron microscopy-energy dispersive X-ray analysis was applied.

On the stability of mediaeval inorganic pigments: a literature review of the effect of climate, material selection, biological activity, analysis and conservation treatments

“…Orpiment and realgar exist as minerals, as well as synthetic pigments [175], and of the two arsenic sulphide pigments, the first one is the most stable. Realgar, being unstable, was less often reported in works of art [1,[176][177][178][179]. It has a polymorphic photodegradation product, pararealgar As 4 S 4 .…”

“…Permanence of orpiment to light was known to be poor, although some intact paint layers could be found on some illuminated manuscripts [176,178,179]. Coarser grain size seem to retard the colour change [30].…”

Identification of artistic materials in paintings and drawings by Raman spectroscopy: some challenges and future outlook

“…Reference Raman spectra acquired in different verdigris powder samples have been reported . Nastova et al analyzed a green pigment in a medieval Slavonic illuminated manuscript by Raman spectroscopy and SEM‐EDS and concluded that it contained an organo complex of copper, and that further identification of the compound/s was not possible by these techniques . Conti et al acquired Raman and FTIR spectra on two fresh copper resinate commercial samples and on a commercial verdigris, as powders and mixed with linseed oil, using different excitation wavelengths, and reported the analysis of a cross‐section sample removed from a painting by Caravaggio, where they suggest the presence of a copper resinate.…”

“…The basic recipes for making these inks include a source of tannins, such as gall nuts, a mineral containing an iron salt, typically vitriol, and a gum solution as a binder. Colorants, such as logwood, carmine, and indigo, were recommended in order to increase the chromatic intensity of iron gall inks, but the complexity of the chemistry of these inks and the difficulties involved in their identification in works of art mainly lie in the numerous recipes used, some calling for boiling the mixtures and/or fermenting them for example, in the variety of sources for the different ingredients, in their propensity to undergo color changes from black to brown, in their corrosive nature, in the fact that different works of art and historic documents have been kept under different environments and have different histories of conservation interventions, and, as expected, this complexity is reflected in the features observed in the Raman spectra …”

Crocoite PbCrO4 and mimetite Pb5(AsO4)3Cl: rare minerals in highly degraded mediaeval murals in Northern Bohemia

“…in the 16th or even the 18th century East-European manuscripts. [26,27] The history of As-based pigments use in non-European countries is not fully evidenced; highly degraded orpiment was identified, e.g. in the mid-19th century Ethiopian mural paintings.…”