I have been using Tmax-100 for years but for the first time yesterday ended up with purple negatives. I have noticed threads on this subject in the past but what is the cause? Can it be corrected by re-fixing and re-washing? The only change in my small tank development process (as far as I know)was a change from kodak to Ilford Universal fixer. Thanks in advance for your help.(posted 9680 days ago)