9. Remove the exposed metal. The result is a shadow of the picture used on the film.10. Remove the top piece of plastic from the film.
11. Develop the picture on the metal by putting it in a glass container filled with basic solution of one tablespoon of washing soda to one liter of water for seven minutes.
12. Check the piece by using a sponge to gently rub the piece while wearing rubber gloves. The film will come off of the areas that weren't exposed (the black areas of the picture) and will adhere to the areas that were exposed (the clear areas). If the lines are not crisp, leave the piece in the developer for another minute and check again.
13. When the outlines of the picture are clear, spray the metal with vinegar, as acid stops the developing process, and rinse well with water. You're ready to etch.
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