user's instructions for positiv-20 Instructions made by Wouter Ferro "free lance research and development person" for Polymetaal   Clean and degrease your plate (copper, but supposedly also other metals) very well e.g. with a sponge and soy sauce. Do not use sand paper as you are going to bite the metal plate. Dry the plate well with paper or cloth. Put the plate horizontally and spray on a thin layer of photopolymere. Keep the spray can more or less vertical at approx. 20 cm from the plate. The drops of the spray spread out to make an even layer in a moment. Do not handle in natural light, because of the UV sensitivity of the material. Dry the plate in a stove (20 minutes, 70 C) or just ambient temperature (> = 24 hours). Supposedly the plates can now be stored in the dark for days or weeks before further use. Expose the plate to a UV source with your transparency (and a aquatint screen if applicable). The sensitivity is roughly the same as that of the photopolymere films (Image on etc). Of course you need to run your own calibrations for your specific lamp and set up. After exposure no image can be seen yet. Develop in a solution of 7 g NaOH (caustic soda) per liter. (note this photopolymere layer does not develop with Sodium carbonate=soda). Developing time will be in the range of 1-1.5 minute. Wash with ample water. Check by submerging your plate a moment in Ferric chloride (or the mordant that you use) if the photopolymere has been removed totally in the dark parts of your image. If not, wash and continue developing some more seconds. When the developing is complete, wash and dry your plate and expose for several minutes to UV to harden. Then bite the copper as you wish. Remove the photopolymere in caustic soda of 30 g/l . This goes very quick, i.e. a few minutes. Wash and dry. You can now print your plate, or work further on it with other techniques. Remarks: Use gloves when handling caustic soda. The spray can contains a gas that cannot be seen as non-toxic. The spray does not seem suitable to make a thick layer to practise intaglio in the photopolymere layer (as done with Image on, Z-acryl and DK photopolymere films). Concentrated sodium carbonate and 'Dasty' do not dissolve this photopolymere. The producer states that the material does dissolve in acetone or similar organic solvents, but for safety, the environment and economics caustic soda is preferable. Positiv-20 spray can be used as an alternative for ready made films like Imagon HD, Z*Acryl etc. The thickness of the layer is however much more difficult to control. Clean the surface of the plate using a very soft sandpaper. Do not touch the already cleaned parts as they will 'rust' very quickly. Degrease the plate with a degreaser. Spray a thin layer of Positiv 20 spray on the copper plate. This is how it should look like right after spraying. If you leave the plate to dry, the photo-sensitive layer will become more continuous. Drying will take 24 hours in dark at ambient temperature, or 30 minutes at 70 Celsius degrees. Next you can proceed the same way as with photopolymer film; expose, through a transparent drawing or/and aquatint screen, with UV light. Exposure times depend on thickness of layer, distance to the lamp, power of lamp, etc. After exposure the plate can be washed out in a 10% soda-solution. The unexposed areas will dissolve in the soda. The exposed areas will be hardened out. Before etching (in ferric chloride) it is advisable to expose the whole plate to UV, to be sure that alle areas are hardened out.