Originally posted by mattt Exhausted fixer IMO
That and/or inadequate washing.
The Kodak Tmax and Tx post 2010 have a pink dye which only disappears after 100% fixing and 100% washing.
If it is marginal you will be ok otherwise you may not have archival negs.
Did not realise Fuji used same sentisation dye.
The Kodak data sheet says
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Your fixer will be exhausted more rapidly with these films than with other films. If your negatives show a magenta (pink) stain after fixing, your fixer may be near exhaustion, or you may not have used a long enough time. If the stain is slight, it will not affect image stability, negative contrast, or printing times. You can remove a slight pink stain with KODAK Hypo Clearing Agent. However, if the stain is pronounced and irregular over the film surface, refix the film in fresh fixer.
Wash for 20 to 30 minutes in running water at 65 to 75°F (18 to 24°C) with a flow rate that provides at least one complete change of water in 5 minutes. You can wash long rolls on the processing reel. To save time and conserve water, use KODAK Hypo Clearing Agent.
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It is easy to process mono changing bag, crown cap bottle opener like Swiss Army knife, plastic developing tank, rubber gloves,...
But do fix for long enough and do use Kodak HCA.
ILFORD PHOTO - Processing a Black & White film
I always fix in daylight after three minutes in fix for double the clear time and agitate like fury...