Ed, the negatives that were 'properly' stained were taken later in the morning, and were of a longer range: say 6-7 stops. One of the negatives was processed as N-2 (very long exposure, needed to rein in the contrast), and the other as N. The first four (which showed no stain) were 3.5-4.5 stops, and were processed for 13 minutes at 70F (as listed in the article on your site, for HP5+).(posted 8210 days ago)Standard dilution was used: 1+1+100. Distilled water ('A' and 'B' included), 75ml in each tube. This is what I've been using since I started using Pyrocat-HD - it's worked perfectly every time. The only difference is when I mixed the chemicals - for the batch of 4, I mixed up 300ml of solution (+3ml A, and 3ml B), and for the second batch, I mixed up 200ml (+2ml A, 2ml B), and discarding the extra 50ml.
If anything, I'd expect that the N-2 negative would be the 'off' one, (since it's processing time was so short) but it turned out fine.
I'm going to do some prints this afternoon/evening, and see how they turn out.
Could this perhaps have something to do with the film?