Photochemical machining is a process directly related to photography, and using similar techniques for printing a "photo" of the part using its scribed negative (the drawing). Instead of printing paper, the image is exposed, through the windows on the drawing, on a sheet of metal which has been coated with a "resist", a light-sensitive material. The resist serves as a barrier to the etching solutions which will be used to literally "eat" the part out of the metal sheet. KEYWORDS for this process: etchers, machiners