Fig. 1. Status of sooty murals on the north wall of Chaoyang cave

Fig. 2. Microscopic observation of sooty murals
(a): High-resolution photo; (b): Microphotograph

Fig. 3. Part of the Bodhisattva on the north wall of Chaoyang Cave
(a): Visible image of the abdomen; (b): Infrared image of the abdomen; (c): Visible image of the feet; (d): Infrared image of the feet

Fig. 4. The Bodhisattva of lower layer on the north wall of Chaoyang Cave
(a): Visible image; (b): Infrared image

Fig. 5. The Bodhisattva of lower layer on the north wall of Chaoyang Cavewith Color tolerance
(a): Part of the image with unadjusted tolerance;(b): Whole image with adjusted tolerance

Fig. 6. The male deity on the west wall of Yuhuang Cave
(a): Visible image; (b): Infrared image

Fig. 7. The famle deity on the west wall of Yuhuang Cave
(a): Visible image; (b): Infrared image