Back in the early days of photography, one coated a piece of glass (glass plate) with light sensitive silver. Then the glass plate was exposed in a camera, and subsequently developed to form a negative image. Placing the plate on a piece of paper treated with light sensitive silver and exposing that a second time yielded a finished print.
Modern photography simplified this process, introducing celluloid film for glass, adding color and one hour processing. Until the advent of digital photography, that is.
This blog is about silver-process (film or analogue) photography and alternative processes.