Investigation of photoinduced deterioration in shadow puppet artifacts collected from the National Shadow Pupperty Museum in Chengdu, China

Shadow puppet artifacts are a special type of cultural heritage made from animal skin, possessing significant cultural and artistic value. However, there is insufficient attention to the scientific preservation of these artifacts, and systematic research on their protection is lacking. In particular, light as an important factor and related conservation studies are weak. This study investigates the photoinduced deterioration of shadow puppet artifacts from the National Shadow Pupperty Museum in Chengdu collection. Based on the xenon arc lamp are a common method of light aging, the modern rawhide samples were aged by the xenon arc lamp to simulate photoinduced deterioration. After artificial light aging, the samples were stored in a stable environment (with temperature maintained at 22 ± 2 °C and relative humidity maintained at 50 ± 5%RH) for 150 days. It attempts to avoid further deterioration of the samples due to drastic cyclic changes in the environment. And continuously observe changes in characteristics during this process to verify the potential reversibility of photoinduced deterioration. Comprehensive assessments were conducted to gauge the extent of deterioration. In order to assess the deterioration, a series of analytical techniques were used. Moisture gain or loss was inferred from mass changes, and colorimetric measurements were measured using the CIELAB formula. Macroscopic and microscopic morphological damage was documented through camera, stereo microscope, and scanning electron microscope observations. Fourier transform infrared spectroscopy (FTIR) assessed amide bond degradation and moisture loss, while thermogravimetry/differential thermogravimetry (TG/DTG) evaluated collagen denaturation and thermal stability. The results indicated that prolonged light exposure caused significant deterioration, including color fading, moisture evaporation, and structural damage such as shrinkage and cracking. The findings indicate that light exposure is a crucial factor in the preservation of shadow puppet artifacts. Therefore, it is essential to implement careful management strategies in museum environments to ensure the protection of these artifacts.