A while back I remember being horrified by a post at Vaulting and Vellum on the defacement of illuminated manuscripts. When you work on less visually elaborate and aesthetically pleasing sources, say administrative letters for the sake of argument, the chance of that kind of sin being perpetrated on your materials is much lower. What is much more common in this scenario is the source which has been damaged by the attempts of past scholars, editors and archivists to read it.
A significant number of thirteenth century letters in the SC 1 collection bear similar evidence of chemical agents having been applied at some time to increase the contrast of ink on parchment. Happily in most cases only small portions of the text are affected, typically at the edges, and often UV can help you see through the murk… if you happen to be in Kew with the original in front of you, that is. When you’re forced to rely on digital reproductions from several thousand miles away, it gets your goat to find that some element of dictaminal rhetoric vital for your argument has been obliterated, to all intents and purposes, by otherwise well-meaning predecessors, some of whom helpfully calendared the contents but failed to reproduce them in entirety. One of these days I will tabulate all the examples of this defacement in SC 1 and by correlating them with editions or scholarship of certain authors point a stern and censorious finger at likely culprits. For now I simply say, “Curse you, Oh archivists of the past!”