Hey, I wanted to share this cool book with you all, and thanks to the "interwebs", I can do just that! I picked up a copy at my local U's library, but it's archived on archive.org in all its glory. George E. Brown's "Ferric & Heliographic Processes" http://www.archive.org/details/ferricheliograph00browuoft The most interesting thing about the book is that it contains actual cyanotypes. Look on page 17, and there are others as well. Interestingly, my copy has different images. Anyways, this book is over a hundred years old now and I can attest to the fact that the prints look absolutely amazing, no deterioration whatsoever. Granted they've been in the dark, but it really says something about the durability of cyanotypes.