The Macclesfield Psalter

Organic colourants

Artists' Materials

The variety of hues obtained with organic dyes is remarkable: yellow, red, purple, tan, as well as light and dark pink. This is related both to the use of different dyestuffs – probably lichen-derived for purple and insect-based for red and pinks – and to different preparation methods, such as the amount of alum or potash added to the dye. The intense purple hue, in particular, seems to have been obtained by layering the purple dye over a base of lead white. Lead white was also found mixed with the dye in the light pink and tan areas. Dark pink areas contain gypsum instead.

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1
Detail of St Edmund’s blue mantle under magnification (16x). The gradation of colour can be noted in the folds. The FORS spectrum (below) shows the characteristic absorption bands of azurite at 1496, 2285 and 2352 nm.
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2
The XRF spectrum of St. Edmund’s light pink tunic (above) shows the peaks of phosphorous (P), potassium (K) and aluminium (Al), which suggest the use of an insect-derived organic red. The significant amount of lead (Pb) detected is due to the addition of lead white to obtain the light hue. The FORS spectrum of the same area (below) shows three reflectance minima at 549, 574, 586 nm, confirming the presence of an insect-based dye, as well as an absorption band at 1446 nm, due to lead white.
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The dark pink border was painted with an organic red, presumably extracted from insects, as suggested by the reflectance minima at c. 559 and 574 nm in the FORS spectrum (above). Unlike St Edmund’s light pink tunic, the border contains gypsum, as the XRF spectrum (below) shows the peaks of calcium (Ca) and sulphur (S) and only traces of lead (Pb).

Prefatory image

St Edmund of Bury (841-869), the king and patron saint of East Anglia, was martyred by the Vikings. His pose is elegantly restrained, his gestures solemn and his expression calm, as he clutches an arrow, the symbol of his martyrdom.

St Edmund’s draperies are modelled with gradations of organic pink, verdigris and azurite (hotspot 1) with lead white, to create a three dimensional effect. The different hues of pink found on the page were obtained by adding different white pigments to a red dye. The light pink in St Edmund’s tunic contains lead white (hotspot 2) and the dark pink in the border instead contains gypsum (hotspot 3).

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