Photogravure is a 19th century printmaking technique that involves exposing a photographic positive onto gelatin tissue, transferring the exposed issue onto a copper plate, and etching the image into the plate in various densities of ferric chloride baths. The entire process takes about three days of work to produce a plate, plus about 20 minutes to print each image, not including drying time. Snapchat is a digital medium in which images exist for up to 10 second increments for 24 hours at a time.
