My mom has a thin copper sheet that my grandfather pressed a design into that is a caricature of my mom when she was little. She also has the caricature art to go with it. The art she has had for a while, but only recently just found the copper sheet. It is still untarnished after over 50 years. She wants to frame it and hang it on a wall to go with the caricature. However, she thought that doing some sort of antiquing to bring out the lines might make the image stand out better on the copper. Antiquing would do it, however I’m not sure what, if anything, I could use that would not damage the copper. Also, if I can antique it, is there anything that would be safe as a sealant that will not react with the copper, or don’t seal the antiquing?
Anyone have experience with copper?