Need and time. As long as film is available, what little time I have beyond work (including giving workshops) and raising three boys has to be used for making art...in my case carbon prints from camera negatives, and some platinum/palladium prints. Taking on making my own dry plates would seriously impact the number of finished pieces I can make in a year. Presently I am lucky to make 5 or 6 a year. The boys have three more years of high school -- perhaps then I can devote the time and space to a totally hand-made working regime. The idea is very interesting from an artistic point of view.