Quote Originally Posted by Newt_on_Swings View Post
It may not have been properly fixed in the first place. you can try and refix it, but the color changes may still remain. This happens every once in awhile, where a student of mine rushes the chemical processes by counting too fast. When I hit the lights to evaluate them, you see them change into a purplish color quickly, which at this point i turn off the lights quickly, and drop them back in the fixer. it gets rid of a good deal of that color shift, but areas still somtimes retain a yellowing.
The solution is simple; your fixer is too cold. That's why your student turns purple when you drop him/her into it in the dark.