Fig. 4
Near infrared spectra of binding media applied on microscope slides: animal glue (red curve), egg tempera (light blue curve), linseed oil (orange curve), peach glue (magenta curve), gum Arabic (blue curve), beeswax (brown curve) compared with the corresponding spectrum of a green fragment from the Selden map (black curve) and the spectrum of cellulose (Whatman CC41, green curve). The spectra are vertically shifted apart for clarity