Puretch processing guide written by Jennifer Page, Cape Fear Press. All rights reserved ©2001-2015.



You can expose Puretch in the sun with excellent results. The sun is the ultimate UV point light and the rays are virtually parallel. Exposure is fast, free and easy. Please read all basic instructions first.

Materials needed:

  • mineral spirits or non toxic CitraSolv Concentrate (don't use regular CitraSolv cleaner in the spray bottle, it contains water)
  • spray mist bottle with distilled water
  • black vinyl or cardboard
  • paper towels


A liquid is used to contact the positive to the surface of the film and plate for exposure. There are three types of film positives that can be used; inkjet, laser, Kodalith or imageset transparency. The Kodalith, imageset positive and laser copies will adhere with water and the inkjet will adhere with mineral spirits or CitraSolv concentrate. If you want to use a drawing you have made it is a good idea to make a digital transparency or laser copy of it so you will not damage the original. Inkjets, kodaliths or laser prints will not be damaged when the correct liquid is used. Laminate the Puretch to the plate as previously described in the basic instructions. Pour a small pool of the mineral spirits or CitraSolv on the middle of the plate directly onto the Puretch film (with top mylar still in place) or mist the surface lightly with water. Place the positive, ink side down on the plate then smooth positive in place with a dry paper towel making sure there is contact over the entire surface and no bubbles. Since edges of the positive have a slight tendency to lift it is a good idea to have a plate slightly larger than the image and trim after etching. Cover plate with one of the light proof materials above to transport outside and expose immediately thereafter.

It should be a sunny day and not overcast. You will have to make test exposures starting around 12 seconds, more and less. Periodic testing with a 21 step Stouffer is good for solar exposure (see basic instructions) because the exposure times will vary at different times of the year. Use distilled water for adhering the Stouffer. If you do a test in mid winter you should retest in midsummer and use these times as a guage for the rest of the year. Hold plate perpendicular to the sun's rays for exposure. Remove cover for the desired time. Return plate to darkroom for normal developing. Remove the positive and wipe off any excess water or solvent with a paper towel. See basic instructions for developing film.