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

Zhuo Li,Xiangyang Song,Rui Dang,Fenghui Zhang

doi:10.1109/jphot.2021.3115418

Abstract

Spectral radiation could cause color damage to dyed cultural relics, and finding a method to obtain a minimum-damage light source is a key issue to be solved. In this paper, the color change behavior of pigments under exposure was experimentally investigated by irradiating 17 typical inorganic pigments used for dyed cultural relics with 10 different narrow-band LED light sources. Through an analysis of the color difference of the test pigments against the amount of exposure, the responsivity equations of the pigments were obtained and a mathematical model for predicting the color damage degree was proposed. The 10 kinds of narrow-band light were combined to obtain 10 6 LED by using the exhaustive method. The Ra, R 9 , and | Duv | value of the above spectra were calculated. Ra≥90, R 9 ≥0, and | Duv | ≤0.0054 were taken as the evaluation basis, and 35,398 spectra that met color rendering requirements were obtained. The established mathematical model was used to calculate the color damage value to find the minimum-damage spectrum, which was then input into a Thouslite LEDCube system for reduction. An experiment was conducted among the minimum-damage LED and 3 randomly selected light sources, and results showed that the minimum-damage LED light source has an obvious illumination protection effect.

Highlights

U NDER museum lighting, dyed cultural relics such as paintings and books are the most light-sensitive exhibits according to the material characteristics stipulated by the International Commission on Illumination (CIE) [1]–[3]
The measurement results showed that the color coordinates of the control group in the dark environment did not change during the 90-day experiment period, indicating that the color change of the test pigments was due to the light source
In accordance with the experimentally measured CIE L∗a∗b∗ color parameters L1∗a1∗b1∗–L6∗a6∗b6∗ after the six test cycles, the color difference values of 17 kinds of dyed cultural relic pigment samples under the irradiation of 10 narrow-band light sources were calculated with respect to the initial state CIE L0∗a0∗b0∗ in each cycle

Summary

Introduction

U NDER museum lighting, dyed cultural relics such as paintings and books are the most light-sensitive exhibits according to the material characteristics stipulated by the International Commission on Illumination (CIE) [1]–[3]. These items have extremely strong light fragility. The chemical effects of ultraviolet rays in the light source and the thermal effects of infrared rays will seriously damage cultural relics, but the two have no effect on visual viewing. The visible spectrum will cause significant damage to cultural relics. The visible spectrum determines the viewing effect and cannot be eliminated. Reducing the impact of visible radiation is a research focus in this field [6]

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Conclusion