Figure 2. Nonlinear optical microscopy imaging of preserved and altered parchment “1639”.

(A) Detail of parchment “1639” (^©CRCC, Laurianne Robinet). (B–E) Preserved area of the parchment versus (F–I) artificially altered area by water immersion. (C,G) Grain side with hair follicles (arrows) and (D,E,H,I) flesh side are compared. SHG signals (green) decrease whereas 2PEF signals (red) increase with parchment alteration and collagen fibers organization of preserved parchment (E, zoom in) is replaced by quite homogenous 2PEF signals in altered parchment (I, zoom in).