JAIC 1998, Volume 37, Number 3, Article 9 (pp. 362 to 372)
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Journal of the American Institute for Conservation
JAIC 1998, Volume 37, Number 3, Article 9 (pp. 362 to 372)




Investigation of the painting centered on whether it had been overpainted. The first step was a thorough examination of the paint surface through a binocular microscope. Compensating visually for the heavy layer of discolored varnish, some peculiar features in the upper paint layers were revealed. First, much of this paint had an odd, shriveled appearance. It was also clear that much of the cracquelure in the paint was not caused by the breaking of the paint, but by the shrinking of the upper layers of paint on a surface to which it was not well bound. The shriveling of the paint appeared to come from its being too rich in medium and therefore unable to dry into a consistent film. Further examination of the oddly textured, shrunken, opaque surface paint of The White Horse showed that it was erupting through fissures in transparent glaze layers that were applied on top of it, an indication that the overly medium-rich glazing had been applied too soon after the opaque layers below it. Although late paintings by Constable occasionally exhibit some defects in paint application, causing “unsightly cracks,” those found in The White Horse were far more severe (Cove 1991, 507). A surface examination with a binocular microscope of the sketch for The Stratford Mill in the Yale Center for British Art, which had probably been reworked by the artist (Rhyne 1994), showed no such faults in the paint. Overall, the examination showed many inconsistencies with Constable's typical technique.

A more thorough binocular microscopic examination raised more doubt concerning the upper paint layers. In many areas the opaque, shriveled paint was deposited in cracks in the paint layers beneath it. Although this is usually a concrete indicator for differentiating overpaint from original painting, it was not such a conclusive observation in this case. The x-radiographs showed that there was a painting of Dedham Vale from the Coombs beneath the visible White Horse, but they only suggested that there was another earlier version of The White Horse beneath the obvious one. Therefore, it was difficult to decide if the paint lay in Dedham Vale cracks or in another painting of the White Horse image. In one particularly interesting area of foliage to the left, drying cracks in a layer clearly from The White Horse resulted from being painted directly on top of a thickly painted, bright green field in Dedham Vale that had not yet dried. On top of the cracked White Horse paint and oozing down into its cracks was a somewhat thick, transparent brown paint that covered a good part of the foreground landscape. This layer was clearly later than the layer that formed the initial painting of The White Horse. By implication, any layer of paint on top of the brown layer, of which there were many, was also later and therefore suspect.

Since the investigation of the surface with the binocular microscope indicated that the painting was probably heavily repainted in a hand other than Constable's, scientific analysis was required for confirmation. On the chance of finding more modern paints in these upper layers, pigment analysis in the form of dispersed samples examined with polarized light microscopy was the first method chosen. The results were confirmed with x-ray fluorescence analysis of the elemental compositions. Unfortunately, comparing the results of these tests against a history of Constable's pigment use found primarily earth pigments, lake pigments, white lead, black, and Prussian blue, all relatively common on Constable's palette (Cove 1991). Although mixtures in the trees contained a high propotion of emerald green, a pigment found less frequently in Constable's practice, the evidence clearly was not strong enough to establish that this paint was applied later. These results would seem to argue against the upper layers being overpaint. However, since it was known that any repainting would date prior to 1883, and because all the pigments in Constable's repertoire could have also been used later in the century, finding all common 19th-century pigments was not unexpected.

Because simple pigment analysis did not prove helpful in this case, sampling by cross section was indicated. Cross sections from several different areas of the painting were taken, mounted, and analyzed through the microscope. Each sample shares an important feature with the two that are illustrated (fig. 6, p. 365). A heavy layer of varnish is visible between two paint layers, with thick applications of paint above the varnish and thin applications below it. In the thinner lower layers there are two distinct campaigns of painting separated by a thin layer of oil. Figure 6 is a cross section taken from the roof of the cottage in the central area of the foreground. It was hypothesized that the layers beneath the oil layer were from the lower painting, Dedham Vale from the Coombs, and that the similar layers just above the oil layer were from the original painting of The White Horse. One notable feature of both layers is their relative thinness and “neatness”; both contain only a few different pigments. The second illustrated cross section shows the same cross-sectioned sample at a somewhat different magnification and photographed in ultraviolet light (fig. 7, p. 365). In this photograph the thin layer of oil and the thick layer of varnish are easily distinguished by their bright fluorescence. Comparison of the two differently lit examples reveals another important feature. The thick varnish layer along the left side shows an area in the shape of an inverted triangle, which is a crack in the lower paint layers into which varnish has run. This is an indication that the varnish had not been applied until after the painting had cracked, and that a considerable length of time had elapsed between the completion of the painting and the application of the varnish coating. The paint layers on top of the varnish layer also run into the crack, indicating that they, too, come later. These upper layers are much thicker and less precise. In many instances they contain mixtures of many different pigments. Under ultraviolet light these upper layers were often highly fluorescent—an indication of a good deal of varnish mixed with the paint. In short, examination of the cross section samples points convincingly to considerably later overpaint by someone other than Constable. The uppermost layers clearly filled cracks in the lower layers; they were applied on top of a thick varnish layer that also was applied later; they were composed of sloppy mixtures in a thick, gloppy application completely different from the layers beneath them, which were typical of Constable; and they were ground in a varnish medium.

Fig. 6. Cross section from the roof of the cottage

Fig. 7. Same cross section at half the magnification as in fig. 6, in ultraviolet light

The later overpaint was so heavy as to almost completely obliterate what was beneath it. From the beginning, the study of the x-radiographs, particularly in the area of Willy Lott's cottage in the middleground, suggested that another version of The White Horse existed beneath the visible one. The evident form on the surface depicted only a single gable on the cottage, but Constable had painted this cottage many times from many different angles, always depicting it as it appeared in nature: as an L-shaped structure with two perpendicular wings and two gables in view. Invariably, the misunderstood representation of the house as it appeared was used by those who argued against the painting's authenticity and was itself another indication that the overpaint had been applied by a different painter. But in the x-radiograph it was clear that a properly rendered painting of the cottage existed beneath the one on the surface. Together with the evidence supplied by the cross sections that there were two distinct campaigns of similarly applied paint underneath the surface paint, it was virtually certain that there was some other version of The White Horse by Constable beneath the visible one. The treatment then required that the demonstrably later overpaint be removed to regain the original artist's intention.

Copyright 1998 American Institute of Historic and Artistic Works