What is the black and white shadow on the surface of metal after etching and stripping?

1. The metal material itself has a high carbon content and is easy to reverse black and white; 2。 The temperature of etching solution is too high during etching. Improper use of cleaning solution will lead to oxidation of metal surface. My product had the same problem before. I went to the etching factory in Chang 'an, and their master told me. I am doing well for them now, and this phenomenon has never happened again. Their service attitude is very good. You can try. Dongguan Xinmao Metal 0769-85433899