Notes on J.C. Witherop and the conservation work on the wings of the Altarpiece
Jack Coburn Witherop undertook the cleaning of the Walkers' side panels of the Crucifixion triptych by
the Master of the Aachen Altarpiece in 1963.
Witherop was a private restorer based in Liverpool who did a lot of work on paintings in the Walker's
collection between the late 1940s and the late 1970s. It was not unusual at this time for major galleries
to have work carried out by private restorers, as institutions rarely had permanently employed conservation
staff. This is a relatively recent phenomenon in most museums and galleries.
The late 1940s and early 1950s saw the beginnings of the conservation profession as we might recognise
it today. Articles relating to conservation issues across a number of specialisms, including paintings,
began to be published in a variety of journals.
The importance of detailed study of both the materials and techniques employed to create works of art
and the materials used for conservation was beginning to be recognised. At a basic level, old established
practices were sometimes being questioned in the light of new thinking, and certain traditional practices
were beginning to be thought unsuitable. New materials for conservation were also being tried.
Inspecting the panels
None of the formal conservation training that exists today was available then except perhaps for learning
while in the job at one of the major London institutions. Jack Witherop was a practising artist, from
which he would have had some knowledge of artists' materials, but the only other training in restoration
he is known to have had early in his career was a brief placement at the Victoria & Albert Museum in
London. He was quite forward thinking for the time in terms of his adoption of conservation principles,
and his awareness of the published literature about suitable materials and techniques.
His important discovery regarding the Walker's altarpiece wings was that the reverses had been completely
covered over by someone in the past. It was only while examining the panels that this became clear.
Witherop's decision was to reveal what lay beneath. The conservation records from 1963 refer to the
removal of the overpaint with 'an emulsified wax - ammonia solvent'. This would have been a kind of thick
paste applied to the surface of overpaint in small sections at a time to soften it, making it easier to
Nowadays, ammonia in this kind of paste form would not be chosen for cleaning due to its high alkalinity.
Recent developments have focused on the use of much less alkaline alternatives, including a variety of
aqueous solutions tailored for particular uses and gelled organic solvent mixtures.
National Museums Liverpool Paintings Conservation
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