I am Sunghan Ha from Yuilsanup. I have been developing and producing silver salt photo developer for over 40 years. I have developed and sold a eco-friendly developer excluding Hydroquinone, a toxic substance. It develops and sells film developer for medical X-ray film, non-destructive (automatic, manual liquid, manual powder) film, Graphic art film, and electronic PCB. ( Consists of 1 each of developer and fixer for all products ) ( I can't tell you about the company because I signed NON DISCLOSURE AGREEMENT. In particular, the developer for PCB passed the test in Europe). I tested it at Kodak in Korea, and the concentration came out better than Kodak. In addition, we can provide you with the desired quality and various conditions. Thank's.