The Missal of Cardinal Angelo Acciaiuoli

Selective use of egg yolk binder

Artists' Materials

This suggests a rigorous, hierarchical division of labour between the main artists, who painted the figures within initials and borders, and their assistants, who provided the ornamental parts of initials and borders. This paradigm is consistent with the results of technical analyses carried out on other contemporary manuscripts decorated by these and other artists, who gathered around the celebrated panel painter and illuminator Lorenzo Monaco. It is worth noting that blue areas painted with precious ultramarine never contain egg yolk, probably to avoid altering the pigment’s purple-blue hue by the addition of a dark yellow binder. 

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1
Detail of the Cardinal’s portrait under magnification (7.5x), exemplifying the delicate faces with long eye lashes, fine modelling and complex layering of flesh tones that characterise the work of Hand A.
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2
Detail of Christ’s face under magnification (25x), showing the delicate modelling of the flesh tones, with subtle brown shadows and pink highlights over a white base layer. The facial features are defined with reddish brown lines and the eyes are outlined in black. XRF analysis (below) allows the identification of lead white (Pb), vermilion (mercury, Hg) and an earth pigment (iron, Fe) in this area.
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3
Detail of the angel’s mantle under magnification (7.5x). FORS analysis (below) reveals the presence of lead white (absorption band at 1448 nm) and a red dye, probably extracted from insects (absorption maxima at 523 and 565 nm), in the pink portion of the mantle. Additional absorption bands at 1730, 1760, 2310 and 2352 nm are due to the presence of egg yolk used as a paint binder.
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4
Detail of the green folds of Christ’s mantle under magnification (60x). The blue particles which can be clearly distinguished were identified as azurite by FORS analysis. The XRF spectrum (below) reveals the additional presence of lead-tin yellow (Pb, Sn) as the yellow component of this green mixture.

The elegant figures with delicate faces are representative of Hand A. The complex modelling and careful blending of the flesh tones demonstrate his remarkable technical skill (hotspots 1 and 2). He used egg yolk as a binder to paint the figures, both in the miniature and in the border (hotspot 3), and favoured mixtures of azurite with yellow pigments to obtain green hues (hotspot 4).