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 Andrew’s tunic under magnification (16x), where diagonal lines of underdrawing can be seen under the orange paint layer. The lower hem is outlined in black and decorated in lead white with a pattern of thin lines and circles. The FORS spectrum (below) identifies the orange pigment as red lead (transition edge at 564 nm).
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2
Detail of the purple mantle under magnification (60x), showing the colour gradation from white to dark purple and the typical craquelure of organic dyes. The FORS spectrum (below) shows reflectance minima at c. 550 and 584 nm, suggesting the presence of a purple dye, likely extracted from a lichen.
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3
Detail of the inner lining of St Andrew’s mantle under magnification (60x), showing the alternating stripes of green and shiny yellow which contribute to the modelling. The elements observed in the XRF spectrum (bellow) allow the identification of these materials as verdigris (which contains copper, Cu) and mosaic gold (which contains tin, Sn and sulphur, S).

Prefatory image

St Andrew, the first apostle to follow Christ, was venerated throughout Christendom. He is shown holding a small book and a saltire cross, the symbol of his martyrdom. His pose is similar to that of St Edmund who is depicted on the previous page, but Andrew’s face is contorted with anguish and sorrow, unlike the serene countenance of St Edmund, the East Anglian king.

St Andrew’s plain orange tunic is painted with red lead, and simple decorations at the hem contain lead white. Thick underdrawing lines are visible through the paint layer in some areas (hotspot 1). The saint’s purple mantle, however, conveys a more three-dimensional effect, obtained with a gradation of colour. The hue, which was favoured by English artists of the first half of the 14th century, was obtained from an organic dye, likely extracted from a lichen, such as orchil (hotspot 2). The inner folds of the mantle are skilfully modelled with alternating stripes of mosaic gold and verdigris (hotspot 3), in a pattern which appears in contemporary English and French manuscripts.

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