Conservation

Colour and pigment

The most startling feature of the 1848 discovery of the hundreds of sculptural fragments concealed behind walls in the church was their colour.

There was a resurgence of interest in archaeology at this time and antiquarian George Weare Braikenridge (1775-1856) commissioned artist William Walter Wheatley to depict the bright paintwork of the discovery for his collection. These drawings are now held at the Somerset Heritage Centre. They provide a fascinating reference for comparison with the fragments as they are now, although it is difficult to assess how accurate a record of the colour they represent.

Project conservators Lynne and Emma arrived in June last year and inspected the remaining frameworks in the north and south transepts, from which the sculptures had been broken in the mid-1500s by religious reformers instructed by Edward VI. Painted colour is referred to as polychromy. Traces of this decoration can still be seen in the recesses of the carved stonework – as shown in this image of the vine trails of the south transept reredos.

Vine trail – south transept reredos

As part of their investigation of the frameworks, Lynne and Emma took minute samples of the paintwork to scientifically analyse and compare to the fragments. The results of their testing are incorporated in the detailed report they produced for the church.

Looking at the sculptures its interesting to speculate on how their polychromy might relate to commonly used pigments of the time. Craftsmen used a range of ingenious methods to achieve the spectacular effects we can see preserved so well at St Cuthbert’s. Although covered in dust and dirt, this photograph of a prophet’s head (from the south transept) shows that a palette of black, white, red and yellow paint was used. Sometimes a stray hair from the paintbrush is found embedded in the paint.

STC/342 Head of a prophet, south transept reredos

In medieval times, black pigments were generally produced from carbon. Charcoal black was made from the pyrolysis of wood or fruit stones.

White pigments produce the brightness so commented on in theses sculptures. Lime white may have been used with other pigments to produce different hues. Chalk white was found in quarries in southern and eastern England, so was a good inexpensive pigment. Lead white was used on both reredoses, including to mix the pale pink flesh tone of the surviving heads. One method for producing this pigment was described by Peter of St Omer (Audemar) in the twelfth century: ‘strips of lead should be suspended above vinegar and sealed in a vessel […] then placed in horse dung for thirty days’ (Merrifield, M., Original Treatises, Dating from the XIIth to the XVIIIth Centuries, [o]n the Arts of Painting, 1848 (1967), p. 120). Lead white was found mixed with carbon black to produce an inexpensive dark blue, used on the north transept reredos framework.

Vermillion red, found on fragments from the north transept reredos, is a deep red pigment derived from cinnabar (mercuric sulphide, HgS).

Red could also be produced from lead or extracted from plants such as madder, or insects.

Earth colours are oxides of iron and produce a wide range of hues from red, pink and purple to yellow, orange and brown. These were readily available to medieval craftsmen and produce good, stable, strong colours.

The paints were laid down on a preparatory colour or ‘ground’. This appears to be a buff/ brown layer which appear to be slightly different between the northern and southern reredoses.

Pigments were mixed with a medium to make the paint. This could be size (animal glue), oil or egg (tempera).

A year on from the start of the project, while there is still so much to learn about the St Cuthbert’s reredoses, the conservators’ investigations will provide fascinating insights into the processes and materials used by the medieval craftsmen in the church.

 

Jo Saunders, Documentation and Conservation Assistant

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