RECOVERY OF PALIMPSESTS
Textual preferences are continuously changing and often render erased texts attractive again to curious readers who seek to access the removed contents even at the expense of removing, obliterating, or damaging the upper texts. Since the early modern period, competing methods have been invented and applied to the recovery of overwritten texts. Earlier methods were intrusive and damaged the manuscripts but often brought the desired results.
Unfortunately, earlier – mostly chemical – methods which were applied beginning from the eighteenth century generated irreversible damages in the treated material. The texts often became legible for a short time, right after the intervention, but afterward, the treated parchment frequently used to change colour, develop rust, and undergo damage caused by being burned from the chemical reactions from various reagents. Because of these damages provoked by the reagents, some scholars have preferred to rely on their intuition and conjectures. Franz Anton Knittel (1721-1792), for example, says in his 1762 publication of the Gothic New Testament palimpsest from Wolfenbüttel, Weissenburg 64: Criticus enim ad codices rescriptos non ut medicus sed ut Oedipus adducitur (“for a philologist should study palimpsests not as if he were a physician but as if he were Oedipus”) [Knittel, Ulphilae versionem Gothicam, p. 219; cited by Tchernetska – Wilson, The Palimpsest in Context, p. 246].
Nowadays, non-intrusive optical methods of deciphering texts are most widespread.
In the 1910s, it was discovered that ultraviolet illumination creates a reflection of faded iron ink of the lower scripts, which helps to distinguish them from the upper script without subjecting them to chemical interventions. Photography very soon recognized the potential of capturing and enhancing these differences. Through a long evolution, this method arrived at multispectral photography or synchrotron X-ray imaging. These flourishing methods revolutionized palimpsest studies thanks to the collaboration between the fields of philology and image science.
Vat. lat. 5757, p. 277 - image with natural illumination (on the left) and image with ultraviolet illumination (on the right)