LED Light scenes for artworks colour perception

Lighting quality plays a fundamental role in the perception of environments and objects. Indeed, in order to guarantee a comfortable and pleasant luminous environment, colour aspects cannot be neglected. This issue is particularly relevant in the field of cultural and architectural heritage’s valorisation, because colour is one of the means to communicate artworks’ meaning. Colour perception is influenced by different factors: light sources’ parameters (as Spectral Power Distribution -SPD, Correlated Colour Temperature -CCT, Colour Rendering Index -CRI); environment and objects’ characteristics; observer’s psychological and physiological conditions. Nowadays the use of LED increases design possibilities, by providing a great range of technical choices. Indeed, these light sources are characterized by high CRI values, various CCTs and, in some cases, the SPD of emitted light can be changed, according to specific requirements. Designers should take advantage of the potentialities of new technologies in order to individuate the most suitable luminous scenario, able to enhance artworks, accounting for their characteristics and environmental conditions. Moreover users’ preferences cannot be neglected. Factors that influence colour perception are not easy to control all together and the use of field tests, aimed at evaluating people preferences, can be useful to investigate the effects of their interaction and to define guidelines for designers. The goal of this paper is to show how artworks’ perception is influenced by light scenes’ and setting’s characteristics. Two case studies will be presented. The former regards a marble altar located inside the “Certosa di San Martino” in Naples (Italy), characterized by decorations with an organics matrix and by a kaleidoscopic chromatic range. Four LED projectors with high CRI values were installed, aimed at the paliotto, two with a CCT equal to 3000K and two with a CCT equal to 4000K. The projectors were located and set up in order to obtain a constant illuminance level on the paliotto's surface, equal to about 300 lux. The latter regards a copy of “La dame en Blue” by Matisse, installed in the Photometry and Lighting Laboratory of the Department of Industrial Engineering of the University of Naples Federico II. In this case 12 settings were considered by combining two CCTs (3000K and 4000K), two illuminance levels (50 lux and 300 lux), three backgrounds (white, blue and red). For each case study, about 20 subjects performed a test, to express their preferences regarding the valorisation of the artworks’ colours. Results show interesting interaction between different parameters analysed during the experiments