Illumination in Museums: Four-Primary White LEDs to Optimize the Protective Effect and Color Quality

Abstract

Traditional Chinese paintings (TCPs), which are characterized by enormous storage and high value, are prone to suffering from radiation damage from museum illumination, such as color fading, discoloration, and color vanishing, especially for the most light-sensitive traditional Chinese paintings that are painted with organic pigments (op-TCPs). Thus, the development of light sources that minimize the damage to TCPs is essential. Meanwhile, the color quality of light sources is also of great importance, and there is a lack of methodology for obtaining light sources with optimized spectra to simultaneously achieve the protective effect and ensure the color quality. Here, changing curves of the CIE DE2000 color differences of pigments were shown as a function of the exposure duration by calculating the periodically measured color parameters in a long-term illumination experiment under four monochromatic lights. Relative spectral responsivity functions of the op-TCPs were deduced by fitting the experimental data and obtained the corresponding equal-illuminance relative damage formulas. Then, damage laws to the op-TCPs and the lowest color damage spectral power distributions that satisfy the color quality requirements of a four-primary white LED model were obtained. Our results can provide the theory and application basis to manufacture white LEDs that are suitable for illuminating op-TCPs; the method can be further used in preparing white LEDs for other cultural relics.

Method to Obtain LED Spectrum Optimizing Protection Effect and Color Quality for Lighting Dyed Cultural Relics Painted With Inorganic Pigments

“…An analysis of the change behavior of the color difference curves indicates that the color differences of all the pigments showed a change trend that began fast and gradually slowed down as the amount of exposure increased, and the inflection point of color difference changed from fast to slow; this phenomenon occurred at the exposure of 2400 W.h/m 2 . This is consistent with the changing trend of previous experimental conclusions, in which four narrow-band light obtained by filtering and halogen lamp were used to illuminate traditional Chinese paintings drew with organic pigments [22]. Other similar studies also have similar change behaviors, which proved the validity of the damage effect study [23], [24], [25], [26], [27], [28].…”

Optimising augmented reality projector light output to balance art conservation, colour quality and energy consumption

“…The changes in lighting equipment can be challenging for conservators, museum lighting designers and curators to balance the needs of conservation and visibility, and successfully deliver an artist's original intent. 1,[15][16][17][18][19][20] Based on the understanding of the effect of light on art, researchers proposed mathematical models and tool, [21][22][23][24][25][26][27][28][29][30] investigated the optimisation of theoretical and commercially available spectra for conservation using different techniques. 11,14,[31][32][33][34][35][36][37] Among many lighting technologies used to optimise light source spectra, multi-primary LED light projectors offer advantages in spatial and spectral optimisation over traditional architectural light sources (Figure 1).…”

“…Based on the understanding of the effect of light on art, researchers proposed mathematical models and tool, 21–30 investigated the optimisation of theoretical and commercially available spectra for conservation using different techniques. 11,14,31–37 Among many lighting technologies used to optimise light source spectra, multi-primary LED light projectors offer advantages in spatial and spectral optimisation over traditional architectural light sources (Figure 1).…”

The mathematical expression of damage law of museum lighting on dyed artworks

“…The light aging experiment is a popular international method to study the lighting damage of cultural relics 10 , 11 , and the selection of experimental evaluation parameters is the key. As a mature chromatic index, the color difference is widely used in the evaluation of color damage of dyed cultural relics 12 – 14 . It is a quantitative evaluation of color change by detecting specimens’ color coordinates before and after irradiation and calculating the color difference value by using the formula.…”