You did fix the plates, right? Development process consists of: Develop. Water rinse or mild acid stop bath for approximately 1 minute. Fix - time depends on type of fixer. Water wash - 20 to 30 minutes in running water or multiple changes of fresh water. A longer wash doesn't hurt. Air dry. The develop, rinse and fix stages should all be at the same temperature. As ideally should the wash stage, but the temperature of wash water can be gradually reduced to that of your cold-water source.