Yellowing will show with inadequate fixing/washing, not saying you did anything wrong, sounds like you are using a two bath fix, hypo clear and proper wash before you start toning. Other than this sometimes you can pick up tone from dirty trays but only as a scuff.

exhausted fixer maybe?

Quote Originally Posted by AndreasT View Post
OK saw this only after reading twice, why does sepia stain after the initial wash when toned and washed again before sepia toning. I would say I always wash properly but of course it is possible I goofed up somewhere.
I doubt it could be up to being badly fixed since I always use two fixing baths.