How to make a photoplate to etch brass or copper using dry film.
Apply film to metal
Insert film covered metal in negative image.
Expose and keep in dark place 5 to 15 minutes.
Remove top film. Develop in Na2Co that has been heated to 30 – 40 degrees C. Adjust concentration to develop in 1 to 3 minutes.
Wash with water and dry.
Etch in Ferric Chloride 20% Water 80%
Remove film in NaOH.