Aside from a boneheaded mistake like leaving the cover of your rangefinder lens on, would the use of a marginal developer (D-76, cooked up 10 months ago) cause the entire of strip of film to be wiped out? I had a roll of Tri-X that I tried to develop in D-76 (1:1, 8 minutes at 20 C) and all the frames came up blank. This is not the first time I've tried to develop film although this was the first time I only went 8 minute. Any clues to pass along? By the way, I had a second roll in the same developer tank and that roll had 80% of the images come out. Thanks!