Quote Originally Posted by Roger Cole View Post
Take a piece of film leader and fix in room light. Time how long it takes to clear. Then fix the film for twice that long.
This is what I have done for many years. Recently I developed 3 rolls of Freestyle's Arista Premium 100 (widely believed to be Plus-X). The leader clips cleared in 2 min, but the film in the tank did not clear completely in 6 (I knew I was getting toward the end of this liter of fixer and extended the fix time from my usual 4-5 min.) This was Ilford Hypam, which I've just recently started using. I had been looking for a good rapid fixer to replace Kodafix or Kodak Rapid Fixer, both of which sulfate too quickly, hence the change to Hypam, which otherwise has been satisfactory. The lesson for me is to start keeping track of the rolls I process in a batch of fixer, and toss it before "clear the leader" test would indicate. Live and learn. For the record, I just mixed up a fresh liter of Hypam and re-fixed the offending rolls, which now look fine.