OPTIMUM ACCESS AT MINIMUM RISK: THE DILEMMA OF DISPLAYING JAPANESE WOODBLOCK PRINTS

This paper describes the evaluation of the lighting policy that the National Museum of Ethnology in Leiden, Netherlands, developed for the display of its nineteenth-century Japanese woodblock prints. Colour measurements during one year on exhibition showed changes that exceeded the limit of one 'just noticeable change' in 50 years specified in the policy. In a series of experiments, members of a test panel were all able to perceive the magnitude of colour difference measured in the prints during exhibition when presented with patches of colour side by side, but only half the panel could distinguish the same change when it was seen in the context of a multicoloured image. The change measured in the prints was judged by the panel to represent an average 'loss of value' of 9%, and deemed to be acceptable over a period of 160 years. The outcome suggests exposure of the prints should be further limited for the benefit of future access.