Initially I found the cyan-blue color of cyanotypes fascinating, especially because not too long ago I had been reading about Preussian blue, the first modern synthetic pigment, and cyan-blue and Preussian blue are the same blue. But I soon found myself curious if I could make my prints look like something more in the landscape of other traditional photographs. In other words to have graytones — or maybe sepia-tones — rather than bluetones. And I had read about a process called “toning” which was mentioned in most online literature on printing methods. Toning is, I suppose, very darkroom 101, but I have no formal education in photography and so it was new to me.
Since I try to keep the technologies I adopt to “kitchen sink” level, I was drawn towards toning techniques that utilize household ingredients. So naturally coffee toning seemed interesting.
(Now, I remember seeing somewhere somebody argue that coffee toning of cyanotypes is in fact technically not toning — it’s dyeing. Chemistry theory is not my forte, so I can’t remember the reasoning, but I will keep it in mind so I can prick up my ears and take notes the nex time I come across some info that relates to this.)
I quickly added a few more ingredients to my toning batch — black tea and tannic acid — and then eventually I simplified the whole thing, landing on a process where I use two separate baths: one with tannic acid followed by one with coffee.