Of the 310 paintings at Knole at least 80 have some level of mould on the surface. Although mould is present or suspected in all rooms, the worst appears to be in the Spangled Dressing room, the Billiard room, the Leicester Gallery and the Reynolds Room and is a direct result of the very poor environmental conditions.
Mould penetrates the varnish and paint layers on paintings causing a white bloom on the surface, flaking paint and degradation of the canvas support. If left untreated this damage can become irreversible.
In order to plan how we improve the environment in the showrooms in the future and how we can conserve the paintings, we need to better understand this mould growth; why it appears on some paintings and not others and in some rooms and not others; what factors influence its growth; how can we conserve the paintings and ensure the mould doesn’t return.
We have just started working with The Courtauld Institute of Art on a research project to investigate this mould problem. Six second year students are undertaking a full survey of environmental conditions in the showrooms, looking at data from the past and present to see how the current building works will affect the conditions.
The Petri dishes will collect mould spores that can then be analysed and identified. Samples have also been taken from the surface of some paintings and again will be analysed and identified. This project will run for 1 year.