User's instructions for the Aerosol PRP positief Fotoresist

(originally made for "positiv-20", but that product is not available anymore. ). We assuma that the PRP positive fotoresist is

Instructies made by Wouter Ferro in 2012


  • Clean and grease the plate (normally copper, but other metals can also be used) with a sponge and soy sauce. Do not use sandpaper because the plate is being etched. Dry the plate well with paper and cloths..
  • Lay the plate horizontally and spray a thin layer of photopolymer on the plate. Hold the spray can approximately 20 cm vertically from the plate. The drops flow together to form an even layer.
  • Do not treat this material under "normal" light, due to the UV light sensitivity of the material.
  • Dry the plate in a drying cabinet (20 minutes, 70 C) or at room temperature (> = 24 hours). The plates can now optionally be stored for days or weeks before use.
  • Expose the plate with a UV light source through your transparent (and possibly aquatint screen). The sensitivity is roughly the same as with photopolymer films (imagon and the like). Of course you first have to perform exposure tests yourself, because of your specific lamp and set up.
  • No image can be seen after exposure. Develop in a solution of caustic soda and water (7 grams of NaOH) on a liter of water. (note: this photopolymer material cannot be developed with soda (sodium carbonate). The development time will be around 1-1.5 minutes. Wash with a little water. Check if the photopolymer has completely disappeared through the iron chloride plate to immerse (or in another etchant), especially look at the dark pieces on the plate, if not everything is gone, wash it again and develop again for a few seconds.
  • When the development is complete, wash and dry the plate and illuminate the plate for a few minutes in UV light to cure. Then etch the plate.
  • Remove the photopolymer in a caustic soda solution (30 grams per liter). This goes very quickly, a few minutes. Wash and dry it. Now you can print the plate or further edit it with other techniques.


  • Use gloves when working with caustic soda.
  • The spray can contains a propellant gas that cannot be regarded as environmentally friendly.
  • This photopolymer appears to be unsuitable for "intaglio-type", with etching only in the photopolymer layer and not in the support (metal plate). This is possible with films such as Imagon, Z * Acrylic and DK films (due to their thickness of approximately 50 microns).
  • Concentrated soda (sodium carbonate) and "Dasty" do not dissolve this photopolymer. The producer claims that the film dissolves in acetone and similar organic solvents, but caustic soda is better for several reasons (sink drain cleaner?).
The following text has been taken from a handbook for making printed circuit boards for electronic applications. There are of course common ground with printmaking.

PRP Positive Photoresist aerosol can be used as an alternative to films such as Imagon HD, Z * Acrylic etc. However, the thickness of the layer is much more difficult to control.
Clean the top of the plate with very soft sandpaper. Do not touch the cleaned parts, these parts will then corrode quickly. Degrease the plate with a degreaser..

Spray a thin layer of photopolymer on the copper plate..

This is what it looks like after applying the layer. As the layer dries, the layer thickness will become more even.
The drying time will be approximately 24 hours at room temperature, or 30 minutes at 70 ° Celsius..