The Dichotomy of Gallery Lighting.

Sight is the principal sense used by most gallery visitors, hence light is an essential element required for visitors to appreciate the exhibits, but light can also damage the precious objects it allows us to see. Therefore, light itself reflects the dichotomy of the gallery collection, the roles of conservation and display. Conservation display lighting standards seek to minimise damage by reducing exposure to visible light and excluding ultraviolet. The 50-lux standard for very sensitive materials is almost universally applied throughout the world - but what does 50-lux mean, and could we be using the wrong equipment and measuring the wrong thing? Spurred by 20 years experience of creative conservation lighting for National Galleries of Scotland and other national institutions, the author has set out to explore why 50-lux does not need to look like 50-lux, how the perception of brightness and colour temperature are related, how we should be measuring conservation display lighting. This paper draws on the results of the author’s perception of brightness tests carried out in experimental gallery settings at Edinburgh Napier University in 2011 and wide ranging literature reviews of studies of the perception of brightness at low light levels.