Art & Technology

The story of the Thornham Parva retable shows how technology is increasingly influencing art history

Conservation and connoisseurship joined at the altar

Rediscovered in 1927 by Lord Henniker in a stable-loft in Suffolk, the Thornham Parva retable is a medieval altarpiece some four metres long and one metre high. It consists of a central Crucifixion scene flanked on both sides by a pair of elegant saints, each standing under a trefoiled gable. Given by its finder to the delightful thatched local parish church, it was persuasively dated in the 1980s to the second quarter of the 14th century on the basis of style and subject matter. There is now broad agreement that it was probably made locally for the Dominican church at nearby Thetford, which was founded in 1335.

Such retables or reredoses (the distinction is at best hazy) were a universal feature in British churches before the Reformation; very few survived the destructive effects of Puritan iconoclasm and the climate. Needing conservation, the Thornham Parva retable was removed to the Hamilton Kerr Institute near Cambridge in 1994 with the primary goal of preserving what remained underneath the various layers of 18th-century and 20th-century overpainting and varnish. It was returned to Thornham Parva church in January 2003 after more than 5,000 hours of painstaking work.

This book is the first of a planned series of monographs from the Hamilton Kerr Institute entitled “Painting and practice”. Focusing entirely on the painting as a physical artefact, rather than on its liturgical or art-historical significance, the book records the painstaking process of conservation. It reaches strikingly similar conclusions to those of earlier art historians, based now on scientific analysis of paint and the wood from which the retable was made.

Until recently, many art historians have discussed their subject matter without much reference to the physical condition of the works they write about, or the extent of past restoration. This has involved a real risk of circular arguments in which judgements concerning how pictures ought to look are based on the experience of previously restored pictures. Technological expertise and connoisseurship are now increasingly in constructive dialogue, as this book admirably demonstrates.

Major subjective decisions had to be made about how best to conserve both the figures and the background, and eventually rather different conclusions were reached, as is explained in detail, and there are fascinating chapters on pigments, as well as on medieval carpentry and tin-relief decoration. Given the extensive loss of medieval paintings in France and England, contributor Jilleen Nadolny insists that we are confronted all the more with “the importance of striving to decipher the original techniques, whatever their condition may be”.

The book ends with a series of thought-provoking reflections by conservator Spike Bucklow on some of the challenges facing this new, fast-emerging discipline of technical art history. For example, it seems that the initial under-drawing of the retable would probably have been invisible to the painters beneath a layer of opaque white priming. What purpose then can it have served? In such circumstances he advocates a willingness to accept uncertainty and ambiguity based on available technical data, not regarding this as evidence of failure so much as: “a legitimate indication of the unknowable”. It remains to be seen whether any external evidence will turn up to explain the presence of a substantial second section of the Thetford altarpiece in the Musée de Cluny in Paris. Its simultaneous survival is surely more than a coincidence, suggesting that both parts were kept together until well after the Reformation. But that is another story.

Originally appeared in The Art Newspaper as 'Conservation and connoisseurship joined at the altar'