Adrian....may I ask you about your ongoing experiences with DD? Are you happy with your results over a variation of films? Reason i ask..... I'm actually pending between DD(-X) or Adox XT-III as my standard developer for B/W - different ones I know.
Its been going fine. As a developer for replenishment it works. Ilford’s listed times produce negatives that are totally usable, though all different contrasts. It absolutely is not xtol though. In my opinion, xtol is the superior developer for most films, though DD is no slouch. I’ve had a few emulsions go through where I was like “wow” when scanning them, but going the other way, haven’t yet seen anything where I’d make a note to use D76 instead. I have been using Ilford’s listed times and have not gone through any sort of exercise to get times that produce the same contrast. Ilford’s listed times produce a zone 1 that is 0.1 above film base plus fog if shot at box speed, and the resulting contrast is whatever it is. Some emulsions are really low contrast, some are really high. I’ve not worked out any times that make a uniform contrast for emulsions that they’ve listed, and don’t plan to.
in terms of day to day operation, xtol is a way cleaner working developer. I have to filter DD quite a bit more as it collects a grey sludge at the bottom of the bottle. It also puts a bit of fog on the inside of the bottle and stains the reels, all things xtol doesn’t do.
in terms of activity, it needs a higher throughput to maintain the same activity level over time, and loses activity faster than xtol does if left to sit, so it’s not as well suited for lower volume users. If I have a slow week or two, it’s best to run a control strip before processing a batch of film and correct it before doing the run as it will have lost enough activity that the listed times won’t be correct. The good news is, it’s easy to correct, and it always loses activity, so it’s a matter of just adding enough concentrate to get the activity level back up. This isn’t a problem if it’s been a busy week, but it will start to drop off if you don’t run a good amount of film that week.
all in all, it’s not xtol, but not bad, just different. I can’t really make any judgements in terms of grain because the contrasts are all different, and that affects the grain.
