Enhancing Visual Perception Using Daylight Digital Modelling: A Case Study of the Whistler Room at Mottisfont, Hampshire

a key objective of this project is to develop detailed mapping of the cumulative exposure and distribution of natural light within the Whistler Room, in order to assist the house steward in making informed decisions on the safety of exposing the artwork in daylight at certain times. The findings of our recent research on the use of daylight in heritage buildings suggest that if daylight conditions are well understood and carefully evaluated they can be safely used to illuminate sensitive historic interiors and artworks in a broad range of settings while meeting conservation guidelines.

A range of digital modelling and surveying techniques will be utilised to document the historic interior and to evaluate the seasonal variations in daylight conditions. The Whistler Room presents a challenge in capturing the illusionary qualities of its artwork that mimics structure on a flat painted surface, thus two modelling methods will be tested. The use of digital technologies for heritage preservation and interpretation is a growing area of interest and a focus for the new ICOMOS-UK Digital Technology Scientific Committee. The detailed seasonal modelling approach proposed here can supply good estimates of exposure and illumination in natural light, which can support informed decision-making on the benign use of daylight to recreate authentic visual perceptions of historic interiors. For example, it can assist with the scheduling of the seasonal deployment of shading to minimise exposure to direct sun. This methodology has wide applicability to the Trust’s portfolio of over 300 historic properties, and to other historic houses, galleries and museums.

The digital surveying will consist of 3D laser scanning and Structure From Motion (SFM) to produce detailed models of the Whistler Room. This data will be utilised for simulating the daylight conditions of the space using Radiance software, an accurate modelling tool. Over 4,000 illuminance visualisations will be produced that can be synthesised to develop a detailed climatic daylight evaluation of the interior.

In addition, a comprehensive digital archive will be provided which will constitute an important element in the Trust’s Disaster Management Plan. Should a disaster such as a fire or flood destroy the room this archive will provide vital information for accurately recreating the interior. The final outcome of the research will be published in an academic paper evaluating the methodologies and the role of daylight conditions on the historic character of the interior and its artwork. Most importantly this collaboration with the National Trust and with the Department of Geography should provide a platform for future research activities, and a potential partnership for further grant applications.

One of the treasures of the National Trust’s historic house at Mottisfont is the ‘Whistler Room’, so-called because of the captivating trompe l’œil interior painted by the celebrated artist Rex Whistler in 1938-9. The artist was commissioned by the socialite Maud Russell to create the dazzling interior for her salon where she entertained the social and political elite of the time. Today, the house at Mottisfont receives around 165,000 visitors a year, many of whom come particularly to see this remarkable room.
The significance of the room relies not only on the painted surfaces themselves, but also on how visitors experience the three-dimensional illusionary qualities of the interior and the role of lighting in shaping that experience. While daylight is a desirable feature in many interior spaces, in sensitive historic buildings preventive measures must be taken to minimise its deleterious effects on fragile surfaces. At present the house steward relies on blocking daylight to the room by keeping the curtains closed and using artificial light to illuminate the paintings.

This research project aims to investigate the use of low intensity daylight during the winter months to create an opportunity to experience the interior in authentic natural conditions without compromising on conservation requirements. The project should serve as a case study on the use of a range of digital modelling and surveying techniques to document historic interiors in three dimensions and to understand seasonal variations in daylight conditions.