A few weeks ago I talked about using the BTZS tubes for E6 development. Today I used the tubes for their intended purpose – developing black and white film. I used an Xtol 1:1 dilution to develop a shot I took yesterday on a farm. I realized that the film had a strange blue streak running across the middle. Thinking that it is the dye (usually pink) in the film, I tried to soak it in the water for longer to remove it. After twenty minutes of soaking, it was still there.
So, I read in the forums (thank you google!) that the dye is actually the anti-halation layer that gets removed through the back of the film. The opinions on the forums differ on whether it is the developer or the fixer that removes the chemical, though I think it is fairly consistent with my observation (the film was loaded such that the middle back of the film was pressed up against the tube, resulting in poor solution access). I was able to clear the film within seconds of dunking it into fresh developer. After a wash and drying, the film looks clear. However, after I re-washed the film (I had to get rid of fingerprints) the color returned, only to fade again after drying. I think that the best way to remove this completely might be to do tray development. Alternatively, I may try to do a tray fixing instead in the future.