Great Tower Dover Castle
English Heritage spent approximately £2 million to refurbish Dover Castle’s Henry II Keep or Great Tower, including a major project to recreate its 12th-century interior and lighting. Its intention was to create an attraction that was markedly different from the usual museum presentation, a sort of ‘time capsule’ with as little obviously artificial lighting as possible. But despite this, the lighting had to enable visitors to appreciate the detail of carefully reproduced fabrics, metalwork and freestanding, movable objects such as furniture. And the lighting had to guide some 400,000 visitors a year through the building without the use of way-finding signs. All of this had to be achieved without altering or interfering with the fabric of the building, and with no new fixings. To complicate matters further, English Heritage had introduced new, stringent guidelines on sustainability and energy efficiency.
In order to tackle this mission impossible, Sutton Vane Associates had first to establish a lighting philosophy for the building, working with the client, English Heritage, and the architect, Purcell Miller Tritton. While it was essential to light key areas such as the main chamber, other areas could be left completely without lighting as long as no two connected spaces were left unlit. This would not only make any lighting appear more natural but, with careful planning, light and shade could be used to help visitors navigate through the building almost intuitively, attracted towards lit areas and away from the dark.
Candles, real firelight and daylight are assisted by IRC low voltage tungsten halogen. The scheme avoids visually jarring effects such as uplighting arches and any spotlighting has been done gently with soft edges. In the Banqueting Hall, for example, heraldic pennants on the walls are not lit directly but by bouncing light off the tables, and whereas a conventional museum might light an object from two points, single fittings with spreader lenses are used to avoid artificial-looking multiple shadows around the exhibits. An 80 metre-deep well was the only exception; it was lit from within with a high-powered narrow beam, to convey its depth.
Sutton Vane Associates’ scheme came in approximately 30 per cent under the budget for lighting and cut energy use by half compared to the previous system. At the same time, it had minimum impact on the fabric of the building and all the changes are reversible. Controls with an astronomical time clock were used to create lighting scenes to match the time of day and year. Changes of scene take three minutes, making the transition imperceptible. The existing cabling was re-used but about half the existing track was removed and new fittings were colour-matched to the restored interior or hidden, whenever possible.