“Restoration” is a very poorly chosen term, and strictly speaking, it signifies something which cannot be done. The genuine restoring of a painting is obviously something which is possible only to its original creator.”
— Max Sourner (1921), The Materials of the Artist
… a picture is never finished. No artist has ever painted an image frozen in time; all painting is a perpetual process, with every scene destined to rearrange its tonal contrasts as time does its work on the pigments. When John Ruskin said, “Every hue throughout your work is altered by every touch that you add in other places,” he might have added, “and all that happens subsequently.” When the artist has been reduced to the dust of centuries, time — sometimes personified by an overzealous restorer — goes on remodeling the colors, bringing darkness here and bleaching there, mocking our attempts to pronounce authoritatively on the coloristic intentions of the image’s creator. Even the simple act of cleaning is, as on art restorer noted, “an act of critical interpretation.”
Today’s extracts are taken from the book, Bright Earth: Art and the Invention of Color by Philip Ball (2001).
… By the eighteenth century there was still not one of the spectral colors with which artist considered themselves adequately supplied in pigments. For blues, azurite and ultramarine were scarce, and smalt, difficult to work with in the first place, had a tendency to fade owing to leaching of cobalt from the pigment particles. (The smalt sky of Valázquez’s otherwise radiant Immaculate Conception, produced about 1618 has turned a depressing brown.) Indigo, an organic dye, was not lightfast. The report of the discovery of Prussian blue in 1710 began by saying, “Painters who mix oil with their colors have few that represent blue, and those such that, rightly, they wish for [some] more satisfactory.”
The richest reds were lakes — primarily cochineal and madder — but these might not last. In Joshua Reynolds’s Anne, Countess of Albemarle (c. 1759-1760), the countess’s pallid face was once a healthier pink; the complexion has become deathly as the color drained from the (probably cochineal) red lake.
Of pure and bright purples there were still none, and for orange, realgar had only ever been used sparingly. Greens were still a particular problem. The Italian Giovanni Angelo Canini commented in the mid-seventeenth century that mixed greens should always be made up “fresher” than they actually appeared in nature because they would darken with age. A century later Robrt Dossie’s Handmaid to the Arts proclaimed that “the greens we are forced at present to compound from blue and yellow are seldom secure from flying or changing.”
This was largely the result of using fugitive yellow lakes. Foliage would often turn a bizarre and sickly blue color as the yellow component (sometimes a glaze over blue underpaint) lost its hue under the influence of light. Pieter Lastman’s Juno Discovering Jupiter with Io (c. 1618) has acquired dark blue-green vegetation, and Jan van Huysum’s Flowers in a Terracotta Vase(1746) had patchy blue leaves owing to the fading of the lake pigment. In 1830 J.-F.-L. Mérimée commented that “in several Flemish paintings, leaves of trees have become blue, because the yellow lake, mixed with ultramarine, has disappeared.”
It was hoped that Prussian blue, discovered in the early eighteenth century, would at least satisfy the desire for a blue to replace ultramarine. But already by the middle of the century, its tendency to fade had become evident. Dossie warned that the lighter, brighter, and most attractive varieties of Prussian blue (which contain white alumina) are “extremely subject to fly, or to turn to a greyish green.” This propensity to fade is accentuated when the pigment is mixed with a high proportion of white, as it often was for eighteenth-century skies. The skies in several paintings by Gainsborough (such as Gainsborough’s forest, c. 1749), Watteau (Récréation italienne, c. 1715-1716), and Canaletto (Venice: Campo San Vidal and Santa Maria della Carita, 1726-1728) are all pearly and washed out where once they would have been a deeper blue.
… The Impressionists and their successors would surely have benefited from the services of someone like [George] Field. As it was they tended to throw caution to the wind — and pay the price. Some of the new pigments, such as cobalt blue and lemon yellow (strontium chromate), aged very well; others did not at all. Zinc yellow (zinc chromate) goes greenish in oil, which proved disastrous for Georges Seurat’s carefully judged pointillism. Discoloration of zinc yellow is apparent in Bathers at Asnières (1883-1884), and the lawn of La Grande Jatte (1884-1885) is peppered with brown spots owing to deterioration of a chrome yellow. There can be few more emphatic examples of how the limitations of materials can undermine an artist’s delicate coloristic intentions.
If painters have difficulty with color stability, digital photographers have it a thousand times worse. We don’t even have a (dis)colored original. We have only a digital file — data — that must be read and interpreted. By what machine? By whom? In what cultural/historical context? We have profiled monitors and profiled paper/printer combinations and software conversions from files to monitor then from computer to printer. We have papers that are, at best known (hoped) to be stable for one hundred years — if, if you have ever managed to get a satisfactory print out of the series of interpretations in the journey from file to paper.