Apart from the chance invention of Prussian blue soon after 1700, the range of colours available to artists changed very little until the 19th century, when modern chemistry came into its own. Painters, of course, were not the only or, in most cases, the main consumers of these colours. They were used, for example, in the dyeing of cloth, the production of ceramics and for the decoration of all types of object, including buildings and sculpture as well as products for domestic use. Thus Venice’s industrial and mercantile strength, rather than its flourishing artistic tradition, made it a centre of the European trade in colours. The current exhibition at the National Gallery, Making Colour (until 7 September), illustrates the characteristics and use by painters of the principal types of pigment, also showing the changes made possible by the introduction of new types of paint after 1800. Most of the exhibits are drawn from the gallery’s own holdings, with a few loans from other museums and private collections in Britain. There is no catalogue as such, but labels are informative and clear, and the main themes, together with many of the specific examples, are discussed in A Closer Look: Colour by David Bomford and Ashok Roy, published by the National Gallery in 2009, the second edition of a book that first appeared in 2000. Most of the rooms are devoted to a single colour, and in addition to paintings there are specimens of pigments and the materials from which they are derived, whether mineral – for example lapis lazuli, which came from Afghanistan and was extraordinarily expensive – or animal or vegetable; the last two were the main sources of different types of red. Particularly striking is a small picture from a private collection, a well-known composition by Orazio Gentileschi, which is painted directly onto a polished sheet of lapis lazuli representing the sky.
The exhibition, then, is overtly didactic, assuming no knowledge on the part of visitors and aiming to show in an accessible way some aspects of how paintings were actually made in the past. At the same time, at various points it touches on the question of how pigments have changed over time. Blues have become greener, or have almost entirely faded; greens have become brown or blue, reds have become pink and some yellows have disappeared; and several of the paintings on display have been chosen to illustrate this. Thus Niccolò di Buonaccorso’s 14th-century The Marriage of the Virgin originally included green trees in the background; the green was achieved by a layer of yellow over blue, but the yellow has now disappeared, leaving the trees entirely blue. Much later Gainsborough was able to use the more stable Naples yellow for a dress in the famous picture of his two daughters chasing a butterfly, and it has survived much better. Colour deterioration was not limited to paintings produced before the 19th century, as can be seen in some works by Van Gogh, who was often obliged to use cheap materials. What is displayed on the walls of galleries today inevitably looks different from the way it looked when it left the artist’s studio, even without taking into account the vexed question of the types of varnish that were used in the past and the way they’ve changed over time. How conscious artists were of these irreversible changes is unclear. A short film at the end of the exhibition illustrates the effect of different lighting conditions on the appearance of paintings, and explains how our perception of colour can depend on our expectations as well as on illumination and context. Viewers’ responses to various questions are sought, but it is not made clear exactly what issues the gallery wishes to explore by this process.
The display works well and is even elegant, but it’s a pity the scope of the exhibition is so limited and its ambitions so modest. In concentrating exclusively on the painters’ materials, the organisers have left aside the larger and more interesting issues of how and why the use of these materials changed so dramatically over the centuries, and of the way the effects that could be achieved with them became so much richer and more complex. This reflects a larger failure in art history over the past century or more. Familiarity with the materials of art, their preparation and use, was traditionally a central element of artistic training, along with some grounding in drawing, perspective and anatomy. This body of expertise and knowledge, acquired by painters before they became independent masters, was normally categorised as theory, the acquisition of which necessarily preceded effective practice.
In the first half of the 19th century there was much research into this kind of theory, in which English scholars played a notable part. They included, for example, Mary Philadelphia Merrifield, the wife of a barrister in Brighton, whose publication of early texts on artistic technique and the composition of pigments is still fundamental, and who, rather unexpectedly, later became an authority on seaweed. But art historians today are much more interested in texts about art which emphasise the parallels or differences between the visual arts and other activities, such as poetry or history, with arguments often drawn from literary criticism or philosophy. For the past century or so, this kind of writing has been routinely categorised as art theory and has been intensively discussed. Much of it was written by non-artists and for the most part it was addressed to non-artists; but it’s easy enough to understand why it has such a strong appeal to academics today. The texts, of course, are worth studying for their own sake, although few of them seem to have had much impact in their own time, or to have appeared in more than one edition before the 19th century. But the result of this type of research has been to divert the attention of art historians from the concerns and priorities of artists themselves, who deserve better.
We need to combine the kind of scientific expertise developed in major museums such as the National Gallery with a more open and inquisitive attitude on the part of art historians to the relevant early written sources if we are to understand more about the way painters worked in the past, and how and why they introduced new techniques and acquired new priorities. Anything that reminds us that paintings are objects whose production required much technical knowledge and manual skill, and often a desire to overcome the physical limitations of the materials used, is to be welcomed. Making Colour shows how much more work is needed.