The materials and procedures of the 19th-century lithographer are duplicated in almost every respect by the contemporary hand printer. An image is drawn with tusche (a carbon pigment in liquid form) and litho crayon before the printing surface is fixed, moistened, and inked in preparation for printing. The printing itself is done on a press that exerts a sliding or scraping pressure.
The dream about keys is a dream that refers to solutions to one's life problems. The question you have to ask yourself when you have this type of dream is 'what is the problem I have today that needs a solution, or a key? (read all at source)
Dreaming of a red door refers to either anger or passion that you are keeping locked up within yourself. If you open the red door, then it means that you are confronting some uncomfortable emotions. To see a black door in your dream symbolizes your personal hidden secrets. If you open the black door, then it suggests that you are exposing yourself to danger. You are proceeding toward a situation despite the risk. Seeing a gray door in your dream indicates that you are experiencing ambiguity in your future.