I've always enjoyed explanations of these processes. In college I studied art, doing mostly photography, and some printmaking. The processes of making photo re

I've always enjoyed explanations of these processes. In college I studied art, doing mostly photography, and some printmaking. The processes of making photo resists for screen printing or intaglio have a lot of commonalities to the rudimentary elements of semiconductor construction, but there's one technique in printmaking that goes a lot farther in its parallels. Photogravure is an intersection of photographic ( drawing with light ) and printing plate processes. A positive transparency ( sometimes called an inter-positive if made from a negative ) is used to expose a photosensitive emulsion applied to a (usually copper, sometimes zinc) printing plate. The emulsion is a "resist" in that it hardens on exposure, and once the non-hardened material is washed off the plate is etched to remove surface material from the plate where the resist has not hardened over it. Once etched to the printer's desired depth, the resist is washed off. The grooves of the plate will then hold ink relative to their depth and width. A printer may repeat the emulsion, exposure, etching (with test printing along the way, inking and printing to confirm that the image is as expected) cycle several times to build up the line quality needed in an image, often starting with the heavier line work or darker "ground" areas of the image and building up to the finer line and lighter textures. Alternatively, while etching, the acid solution may be washed from the plate and finer work painted over by a new layer of rosin-based resist to keep them from further etching. There are fun parallels between inking and doping, but multi-color prints would be built up and printed from separate plates or states of plates. It's important for us computery folks to remember that just because the kernel of a process is ages old, doesn't mean it isn't sophisticated or high-craft. After all, there is nothing new under the sun, but if you can find a way to present something in a new light, that's innovation.