Does anyone know a good book on the history of photographic technology? I have seen lots just on cameras and lots more on the history of photographic imaging/thought, but none on the technology as a whole. The image histories have brief accounts of the very dawn of photography, but then go on with things like "with the increase in film speeds towards the end of the 19th century X became possible", OK so how did they get faster? The camera books just tell me how to tell a model X from a model Xa, which would be great if I was into camera collecting, which I'm not. Any ideas? David.