New tools for managing daylight exposure of works of art: case study of Hambletonian, Mount Stewart, Northern Ireland

Blades, Nigel; Lithgow, Katy; Cannon-Brookes, Stephen; Mardaljevic, John

New tools for managing daylight exposure of works of art: case study of Hambletonian, Mount Stewart, Northern Ireland

Resource type

Journal article

Creator (person)

Blades, Nigel

Lithgow, Katy

Cannon-Brookes, Stephen

Mardaljevic, John

Date published

February 6, 2017

Abstract

An applied research project to protect one of the most important paintings in the National Trust from excessive daylight exposure is discussed. Hambletonian, Rubbing Down, by George Stubbs RA, hangs below the roof lantern on the main staircase at Mount Stewart, Northern Ireland. In one of the first applications in a UK heritage building, the research employed climate-based daylight modelling (CBDM) to understand the fall of daylight on Hambletonian, its annual light exposure and the effect of proposed light control measures. The light control options were proposed by Stephen Cannon-Brookes and John Mardaljevic included reducing wall and ceiling reflectance by changing wall colour, reducing overall transmittance of glazing by introducing external screening, possibly for use during summer months only, and introducing partial, directional shading to reduce direct sun at key times of day and year. Automated mechanical blind control was ruled out because of complexity and the likelihood of failure. The option of introducing external shading was considered the most suitable form of light control, especially on the grounds of simplicity and ease of maintenance. The project architect researched materials for external shading and methods of fixing to the dome. An insect screen mesh was chosen as the material for the prototype and this was to be cut into segments to match each of the 16 glazed panels in the dome, sewn together and then stretched into place over the dome and secured using clips and guy ropes. The simulations showed that repainting with the darker paint finishes would reduce the annual light exposure from 3.5 mlxhr to 2.5 mlxhr.