10 HISTORIC PAINTS AND DECORATIVE FINISHES COLOUR, PIGMENTS AND PAINT - SOME HISTORICAL COMPONENTS Pigments exist in all materials whether or not they have been positively coloured; they are responsible for reflected colour when light falls upon the surface. The most common source of natural pigments is the earth and it is in these so-called 'earth colours' - of sand, gravels, clays and rocks - that we can see the greatest affinity with natural materials. The commonest and most durable are the reds and yellows - the ochres - derived from iron. They were freely available locally and were used in East Anglian colourwash. Bur they were rarely pure enough for painting, which demanded consistency. For this special sources were used: yellow ochre was imported from Oxfordshire, red from Devon and umber from Cornwall. With the application of heat, burnt umber and burnt sienna could be produced, but more complicated, expensive and sometimes dangerous processes were needed to produce brighter and more adventurous colours. These included red and yellow from lead, green from copper and blue from cobalt, all of which can be seen in 13th century paintings on the vaulted ceiling of rhe cathedral Treasury. The alternative azure blue, produced by grinding rhe semiprecious lapis lazuli, was so expensive char ir was reserved for special works of art such as illuminated manuscripts, and then often only for the Virgin's gown. Other medieval pigments included vermilion from sulphur, and gamboge, Naples yellow, orpiment and verdigris, from oxides of lead, antimony and tin. Although a considerable number of colours were available during the Middle Ages, the difficulty and cost of production made many of chem expensive and curtailed their use until well into the 18th century. There was, for example, a deficiency of bright yellows and blues cheap enough co use in quantity. When Prussian blue was first introduced in 1704 it became the most popular blue until it was displaced by synthetic ultramarine in 1828. For normal everyday use 'common colours' described in a Builder's Price Book of 1787 were "white-lead, or stone-colour, lead-colour, cream-colour, pearl-colour, wainscot-colour, chocolate-colour", all off-whites, greys and browns made by mixing white lead with relatively inexpensive red and yellow ochres, and black; a range of colours surprisingly familiar to the 20th century householder. To these common colours, 'olive' or 'invisible' greens were added early in the 19th century as "being proper for covering gates and rails, in parks, pleasure grounds etc. by rendering them in a measure invisible at a distance on account of its approximation co the hue of vegetation". This is undoubtedly the origin of the custom still practised by park keepers and farmers alike, although the original greens were quite dull, being made from a mixture of poor quality Prussian blue with black and yellow ochre. During the second half of the 18th century Vanherman describes a dull red ocre as: "Excellent for barns, ~heds, cart and waggon wheels, implements for husbandry etc." a custom which has persisted in the red colour still commonly used on 'Dutch' barns in Britain. The description also fits that of 'Suffolk pink', a deep red ochre used to colour the distemper on walls of buildings in Suffolk. Distemper - or whitewash - was the paint most commonly used from the 12th century until well into our own times. Being made from chalk or lime, it was freely available and very cheap. It could easily be coloured and it provided a suitable light-reflecting surface for inside walls, as well as protection against the elements for the exteriors. There were several recipes: whiting bound with size, preferably starch because it did not impair the colour; alternatively, slaked lime mixed with powdered alum instead of size or starch, or 'stucco whitewash' made from chalk lime slaked in boiling water and mixed with ground rice. A recipe of 1396 includes size made from boiled strips of leather; and at various times and in various places egg yolk, beer, wine, sale and potatoes were added. Colour-wash was made by simply adding pigments such as red or yellow ochre, verdigris (green) - which was liable to fade or lime-blue, made by precipitating copper sulphate with milk of lime. The origins and application of colourwash must have been very variable, in spite of the reports of contemporary writers such as W. Harrison, writing in 1587, of the practice to "strike over our clay works and stone walls, in cities, good towns, rich farmer's and gentlemen's houses wieh asbestos or white lime". In this context the term 'white' should be liberally interpreted, the likelihood being that much of the lime-wash either contained traces of pigments from the source or acquired them from the clay walls to which it was applied. In most places the effects were probably very mixed, with a few houses white, some yellow or reddish, and some with the clay of the wattle-and-daub still visible: an effect which was portrayed in some of the paintings of the Norwich School as late as the 18th century, and which can still be seen in some of the French and German CONTEXT 40
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