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As an important substrate of traditional Chinese cultural relics in museums, paper is the material with highly light sensitivity, which is susceptible to irreversible lighting damage. To provide high-quality viewing, it is vital to study the parameters of light sources in consideration of paper substrates' long-term conservation. As an important factor affecting both conservation and viewing, there are some issues concerning correlated color temperature (CCT) in the relevant standards, namely, the inconsistent recommended values. In this research, paper samples were subjected to accelerated irradiation experiments for 1440 h by 10 narrow-band lights in the visible range, and the infrared spectra were measured periodically. The calculated oxidation index was used to obtain the damage response function to different spectral wavelengths and exposures. Subsequently, using the method of exhaustion, 9477 spectra with a CCT range of 2650–4150 K that met the viewing requirements were screened, and lighting damage to paper substrates was calculated using this function. Based on that, the correlation between CCT and lighting damage to paper substrates and their standard deviations was obtained. Combining the previous research on recommended for CCT pigments, a preliminary recommended CCT of 3100–3200 K in selecting light sources for traditional Chinese paper relics was proposed. It is worth emphasizing that it is still necessary to use the spectral power distribution of light sources, as the underlying independent variable that leads to damage, to further calculate the lighting damage using the function mentioned above to achieve protective lighting. [ABSTRACT FROM AUTHOR]

As the substrates of traditional Chinese painting and calligraphy, paper and silk are susceptible to optical radiation in museum illumination, resulting in mechanical damage, the origins of which are changes in microscopic molecular structure. However, there is no effective method of quantitatively evaluating the microscopic molecular structural changes caused by irradiation. In this study, Raman spectroscopy was introduced for illumination research on the paper and silk substrates in museums. Four narrow-emitting light sources with different peak wavelengths, red (650 nm), amber (583 nm), green (510 nm), and blue (450 nm), which together constitute the spectrum of a white light emitting diode (LED), were used as experimental light sources. As experimental specimens, paper and silk substrates were irradiated by the four light sources. The Raman spectra of the specimens were collected before and after the illumination. By analyzing the variations in characteristic Raman peak intensities, the relative damage coefficients of the four light sources on microscopic molecular structures in the specimens were studied. Then, we were able to design the white LED spectral irradiance distribution of the two substrates according to the corresponding damage coefficients. In conclusion, a research method for studying the microscopic molecular structural changes in the substrates of traditional Chinese painting and calligraphy based on Raman spectroscopy has been proposed, finding a solution to the long-standing challenge of how to quantitatively evaluate illumination-induced mechanical damage of substrates. These results are instructive for designing the spectral ratios of white LEDs suitable for illumination of traditional Chinese painting and calligraphy in museums. [ABSTRACT FROM AUTHOR]