Fig. 1.

a The Archimedes Palimpsest before treatment, showing intense purple stains and large areas of degraded parchment. b The picture shows the folios 68v-69r of the manuscript before the conservation treatment; the three sample sites swab AP1_ f.68v, taken from the lower left corner and swab AP3_ f.68v, from the center of the outer margin (locations A and B). The third swab sample was collected from a healthy area near a sewing hole along the centerfold that showed no visible damage: sample AP2_ f.68v (location C) (Images taken at the Walters Art Museum are copyright of the owner of the Archimedes Palimpsest)