Fig. 1. The full band reflectance spectra (350~2 500 nm, a) and selected region spectra (1 100~2 400 nm, b) of three binders
Blue=egg yolk; red=rabbit glue; green=linseed oil

Fig. 2. The reflectance spectra of egg yolk mixed with cinnabar in the range from 1 100~2 400 nm
Blue=egg yolk+cinnabar; red=egg yolk;green=cinnabar

Fig. 3. The reflectance spectra of egg yolk mixed with azurite (a) and lapis lazuli (b) in the range from 1 100~2 400 nm
Blue=egg yolk+ azurite (a)/lapis lazuli (b);red=egg yolk; green= azurite (a)/lapis lazuli (b)

Fig. 4. The reflectance spectra of three binders mixed with yellow ochre in the range from 1 100~2 400 nm
Blue=egg yolk+yellow ochre; red=rabbit glue+yellow ochre; green=linseed oil+yellow ochre; black=yellow ochre

Fig. 5. The first derivative spectra of three binders in the range from 1 100~2 400 nm (a), 1 150~1 250 nm (b) and 1 650~1 800 nm (c)
Blue=egg yolk; red=rabbit glue; green=linseed oil

Fig. 6. The first derivative spectra of three binders mixed with lapis lazuli (a) and yellow ochre (b) in the range from 1 100~2 400 nm (a)
Blue= rabbit glue+lapis lazuli (a)/yellow ochre (b); green=egg yolk+lapis lazuli (a)/yellow ochre (b);red=linseed oil+lapis lazuli (a)/yellow ochre (b)