Distributed Proofreaders is a site to “help ease the conversion of public domain books into e-books” in the mission of “preserving the literary history of the world in a freely available form for everyone to use.”
DP has adapted a font for proofreading that is supposed to be easier for readers to distinguish similar characters (lowercase Ls and ones, for example) and often-overlooked errors (e.g., rn looks like m).
Guess it makes sense that there’s an optimum proofreading font. I always just used a nice, fat serif font when I had a choice. Often, I didn’t have any say in the matter and had to do the best I could with 9-point Interstate Light Condensed.
Still, I’m not sure this proofreading font, DPCustomMono2, does much for me — it actually makes my eyes hurt a little. But maybe I’m just not used to it.