Project Gutenberg makes non-copyrighted texts available on the internet. They use a team of distributed volunteer proofreaders. Today they announced that the distributed proofreader project has just completed its 25,000th book, and I think it is fun that it happens to be The Art and Practice of Silver Printing by Capt. Abney and H. P. Robinson.
I wasn't completely sure what forum for this, but since the book has a picture of a contact printing frame on the cover, I thought here might be appropriate.
Cool! Henry Peach Robinson, the guy with the great name and inspiration for all of the combination printers that came after, Jerry Uelsmann especially. This should be worth a read.