The Pabenham-Clifford Hours

Tooling and decoration of the gold leaf

Artists' Techniques

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1
Detail of the Virgin’s pink mantle under magnification (60x). The craquelure suggests that the red colourant is organic and the XRF spectrum (below) shows the peaks of aluminium (Al) and potassium (K) from the alum used to manufacture the dye. The presence of phosphorus (P) indicates that the dye was probably extracted from insects. Peaks from calcium and sulphur (Ca and S, from gypsum) and lead (Pb, from lead white) are also visible.
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2
The XRF spectrum of Gabriel’s dark pink tunic (above) shows the peaks of phosphorous (P), potassium (K) and aluminium (Al), which suggest the use of an organic insect-derived red, and a significant amount of calcium (Ca), pointing to the addition of chalk. The FORS spectrum of the same area (below) shows a reflectance minimum at 555 nm, confirming the presence of an insect-based red dye.
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3
Detail of the Virgin’s face under magnification (20x). The face was painted on a white base, which the features in the FORS spectrum (below) identify as a mixture of lead white and gypsum (absorption bands at a 1446, 1941, 2212 and 2323 nm). This base layer was shaded with a light brown dye and the facial features were outlined with carbon black.
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4
Detail of Gabriel’s wing under magnification (60x), showing numerous blue particles and a few red ones in a white matrix. The characteristic features of lead white, azurite and an insect-derived organic red can be seen in the FORS spectrum below (reflectance minima at c. 560 and 583 nm; absorption bands at 1446, 1493, 2213, 2283 and 2352 nm).
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5
Detail of the decorated gold background under magnification (7.5x). Arsenic (As) and sulphur (S) were detected by XRF (below), suggesting the use of a yellow arsenic sulphide pigment, possibly orpiment, for the spiral decoration applied on top of the gold leaf.

Underdrawing for the draperies is visible in the infrared image, as well as through the semi-transparent paint used in the Virgin’s pink mantle. This garment was painted with a mixture of an insect-based red dye, lead white and gypsum (hotspot 1), while Gabriel’s dark pink tunic contains a red dye mixed with chalk (hotspot 2). Gabriel’s blue-grey wings contain azurite blue and small quantities of an organic red, as can be seen under magnification (hotspot 4). The tooled gold leaf in the background was additionally decorated by painting a pattern of spirals with an arsenic sulphide yellow pigment, likely orpiment (hotspot 5).