Page - 227 - in The Vienna Genesis - Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment

Hofmann, Rabitsch, Malissa, Aceto, Uhlir, Griesser, Calà, Agostino, Fenoglio 227 The grey tones also show a wide variety of mixtures and shades. The pigments employed range from lead white, azurite, indigo to brown earth pigments and carbon black. Accents are sometimes set with orpiment, lead white and madder. The blue-grey colour of the river Jabbok that Jacob crossed with his family shows severe losses. The copper ions of the pig- ment azurite have degraded the parchment. The incarnate parts were painted in a broad spectrum of shades. The mixtures seem to contain red lead, ochres, lead white and sometimes small amounts of madder. In the shades, azurite, indigo and a brown earth pigment appear to be added. The face of the sleeping Joseph on folio 14, page 28, shows in how many hues artist C painted skin. Under the microscope at 10x magnification, different pigment particles can be distinguished. The black pigment seems to be mostly carbon black. Raman spectroscopy of a loose black colour particle indicates carbon black. On the IRR images contours, folds of cloth, faces and hair are painted in fine brush lines. Grey shades in the bodies of animals or contours are applied with thicker brush strokes. Buildings and tents are accentuated with dark grey and black forms. The most distinguishing feature of painter C is the use of azurite as blue pigment (Table 2). Azurite was mixed with other pigments to achieve green, grey, violet and flesh tones. The presence of azurite resulted in migration of copper ions and severe losses in the miniatures. Artist C employed a wide range of pigment mixtures to paint shades of blue, green, pink, violet, and brown. Palette of Painter D: folios 15–16, pages 29–32 Painter D depicted further scenes of Joseph’s life (Gen. 37, 9 to 39, 18). He used a mixture of ultramarine and Egyptian blue as blue pigment. Highlights were painted in lead white. Shaded areas were mixed with indigo. The XRF spectra indicate ultramarine blue and a copper containing pigment mixed with lead white (Fig. 30). Egyptian blue is a synthetic pigment with the formula CaCuSi4O10, which was widely used in Antiquity in Mediter- ranean areas16. It was employed on miniatures in illuminated manuscripts until the Middle Ages and was identified in the Carolingian Godescalc Evangelistary17. The identification of Egyptian blue by means of FORS is given by the absorption maxima at 628 and 780 nm as well as by the typical luminescence emission at 950 nm (Fig. 2). The absorption at 600 nm suggests that the main pigment in the blue paint is ultramarine mixed with Egyptian blue. The presence of Egyptian blue could be confirmed by means of infrared (IR) photog- 16 Eastaugh et al., 2004, A Dictionary of Historical Pigments, pp. 147–148. 17 Denoёl et al., 2018, pp. 13–14 Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0