Leaves from Laurent d’Orléans, La Somme le roi

Degradation of verdigris

Artists' Materials

The visible alteration of the green areas on MS 192 is due to the typical degradation of the binding medium around the particles of verdigris, following exposure to light. The pigment has also ‘bled through’ the support and its reaction with the parchment has yellowed the area. The presence of lead white mixed with the green pigment may have further promoted the yellowing and dehydration of the proteinaceous binding medium.

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Detail of Equity’s tunic under magnification (32x). The tan-coloured paint shows extensive craquelure, typical of organic colourants. The low tinting power of the dye allows the grey lines of the underdrawing to show through the paint layer.
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Detail of the degraded green area in the sea below Noah’s ark under magnification (32x). The FORS spectrum (below) shows the characteristic features of verdigris (reflectance maximum around 547 nm, reflectance minimum at 720 nm, constant rise up to 1400 nm) and lead white (absorption bands at 1444 and 2325 nm).
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Detail of Cain’s shovel under magnification (60x), showing a metallic grey layer applied over a white base layer. The XRF spectrum (below) shows the presence of silver (Ag) in the grey paint, along with high amounts of lead (Pb) due to lead white underneath.
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Detail of the gilded background decorated with rinceaux motifs under magnification (12.5x). The brown remains of the original decoration are visible. The XRF spectrum (below) shows that the brown decoration (blue line) contain more iron (Fe) and potassium (K) than the surrounding gold leaf (red line); this suggests the presence of an organic material, likely a binder or glue, possibly tinted with an earth pigment or an iron-based ink.
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Detail of animals in Noah’s ark under magnification (7.5x). Grey underdrawing outlining the animals’ features as well as a decorative pattern of quadrilobes can be seen through the white paint layer, and it is even more obvious in the infrared image (see Layers).

Full-page miniature in four compartments

The miniature contrasts the virtue of Equity (Fairness) with the vice of Felony. At the top left is Equity represented as a female figure, trampling on a recumbent wolf, and holding a plumb line and a medallion emblazoned with a lamb. Her tunic shows a craquelure pattern and the light tan colourant appears to have faded significantly, with both observations suggesting the use of an organic red dye (hotspot 1). The virtue is alluded to more obliquely by the depiction of Noah’s ark, in which the pairing of the animals suggests an equitable arrangement. The green areas below the ark, as well as the inner folds of Moses’ mantle, show severe degradation of the pigment (hotspot 2). The vice of Felony is not represented by a female personification, but is exemplified instead by images of Cain killing Abel, and Moses restraining two combative men. The shovel used by Cain was probably painted with shell silver over a thick layer of lead white (hotspot 3). The gold leaf in the background is decorated with a pattern of rinceaux motifs, which appear as darkened lines (hotspot 4).

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