This process, solar plate printmaking, uses a steel plate with a special coating that reacts to UV light. No acid needed to etch, you just expose the plate and then wash the areas that were not exposed to remove the coating.
While I did have fun with this process, and think it has some appeal, I just can’t get the texture I want from it. The resulting images look too much like a photograph of the knitting. The closest I came was with the bottom image, which I actually used the knitted sample, rather then a transparency to expose the plate. This works relatively well for open lace work. Still not an etching though.