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A material used as a light sensitive coating for a type of plate that is used for digital platemaking. A plate with a hybrid emulsion has a metal base with two different photosensitive layers. The top layer is made with silver halide, which can be exposed optically or digitally. The bottom layer is a conventional photopolymer, which is sensitive to ultraviolet light. The top emulsion layer is exposed and the plate is processed to remove the unexposed portion of the top emulsion layer. The exposed portions of the top layer act as a mask for the bottom emulsion layer. The plate is then exposed to ultraviolet light, which reacts with the unmasked portions of the bottom layer. The plate is then processed, which removes the mask and the exposed portions of the bottom emulsion. The bottom layer is what is used for the printing process. Some of the resolution can be lost because of the dual exposure technique, but the plates are still rated for a 200-lpi resolution and can handle press runs of over 1,000,000 if post-baked. A hybrid plate has two separate types of waste products to dispose of: silver and photopolymer. The silver is a toxic heavy metal that is under strict government regulations for proper disposal. The photopolymer residue is safer to work with and has fewer restrictions for proper disposal. Hyrbrid plates for CTP have become increasingly less popular and are now rarely used.
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