BCD 2018

INTERIORS 5 161 C AT H E D R A L COMMU N C I AT I O N S C E L E B R AT I N G T W E N T Y F I V E Y E A R S O F T H E B U I L D I N G CO N S E R VAT I O N D I R E C TO R Y 1 9 9 3 – 2 0 1 8 WALL PAINTINGS and ENVIRONMENT LUCY KASZEWSKA W ALL PAINTING techniques evolved from cave paintings created with dry earth pigments and they can include a wide range of traditional and modern materials. The paintings may be executed on a variety of substrates, traditionally plaster, stone or timber, but also canvas permanently attached to a structural support. They can be composed of figurative or purely decorative features, free-hand painted or stencilled and frequently incorporate other materials such as metal leaf. Because they form a very thin layer at the interface between the wall and the environment, wall paintings are integral to the larger host structures and are affected by changes in the latter’s stability and environmental conditions. As a result, they are highly vulnerable to deterioration and conservation can be challenging: any attempts to treat the paintings in isolation from their environment would be doomed to failure. While a generic remedial treatment strategy applicable to all wall paintings would clearly be impossible, this article aims to outline a general conservation approach based on the specific nature of wall paintings. CONSERVATION APPROACH Approaches to conservation have evolved over several decades. The early, mainly aesthetically oriented restoration methods were based on insufficient research and evidence, frequently proving more harmful than beneficial. Current best practice prioritises minimal intervention because the exact outcome of change is never fully predictable. Emphasis is placed on initial investigation, beginning with the key question of whether any treatment is really necessary. This can only be answered after a condition assessment has established whether the issues are ongoing and whether imminent losses would occur without intervention. Diagnosis of the causes of deterioration should start with a survey of the object, preferably in graphic, photographic and written format, gathering all available and relevant information on the history of the building, alterations and additions. This initial assessment should aim to identify the probable reasons for damage and/or deterioration, and a programme of further investigation and monitoring may be required to confirm and understand the cause. The breadth and depth of investigations should always be tailored to the specific purpose, as should the presentation of the findings. Following the initial investigations a decision needs to be made on the way forward. Addressing the causes and activation mechanisms brings more effective results than attempts to strengthen the object by remedial work. Priority is therefore given to preventive conservation measures such as essential maintenance work, followed by passive treatments such as environmental control. This requires very accurate identification of the reasons for failure, targeted, frequently multidisciplinary methodology and further monitoring of the impact of the measures on the painting. Carefully planned and used where appropriate, preventive and passive measures can minimise the need for interventive and often costly conservation in the future. If passive or preventive measures alone are insufficient or not feasible, remedial treatment must be considered in order to strengthen the wall painting and avoid further decay. Much compromise is frequently required between various approaches, but the common aim should be to postpone and minimise the need for invasive treatment. SURVEY AND MONITORING Often observation alone can quickly indicate the possible causes of deterioration. The location, form and nature of any degradation seen on the wall painting’s surface will generally suggest the agents/substances and processes responsible. Even before entering the building much information may be gleaned: • Does the building exterior look well maintained and water-tight? • Are there visible cracks, open joints, moss growth, blocked or broken drains and gutters? • Are there signs of persistent damp in the walls such as salt efflorescence, ‘tidemarks’, or flaking paint, stone, brick or render within the reaches of rising damp, or due to leaking gutters and drains? • Is there potential for the pooling of rainwater (ground sloping towards the building, proximity of a watercourse, impervious paving adjacent to walls, etc)? Once inside the building: • Is there a smell of damp? • Does the floor show signs of damp? • Do the bases of the walls exhibit tell-tale signs of rising damp (frequent re-plastering, possibly using impervious cement, etc)? • Is the floor level lower than the ground level? • Are there signs of surface condensation or water ingress (typically dribble or run marks)? • Is the wall painting adjacent to any of the above-mentioned defects? • Is the wall painting located on an external or internal wall, near a source of heating or ventilation etc, or exposed to sunlight? Answers to these questions may be verified and quantified using instruments as outlined below. If there are no observable building defects or problems, instrumental investigations are perhaps even more important. Thermal imaging is a quick and effective survey method, which may highlight the main areas of concern within the paintings, Beverley Friary, East Yorkshire (All images: Hirst Conservation)