Fig. 4
ATR-FTIR chemigraphy mapping of fenjian. a ATR photomicrograph on cross section of fenjian (×50 magnification); b pigment layer mainly contained white lead (located in no. 1, 1415 cm−1), c paper fiber (located in no. 2) consisted of cellulose (1100–1000 cm−1); d ground ash (located in no. 3) indicated the existence of talc (3674 cm−1), lime (1405, 876 cm−1) and clay minerals (1021 cm−1). Blue and red represent lower and higher concentration respectively