Small tank agitation w/reels - uniformity?

[justpete]

Originally Posted by Tom Hoskinson

I use Hewes SS reels for both 120 rollfilm and 35mm - I presoak with tempered DIW, I always fill the tank with developer. I always agitate gently. My development times are always 10 minutes or more. No uniformity problems, no streaking, with any of the developers I use.

Good to hear there's hope for me yet then.

I take it you don't use much rotation (if any?) when inverting?

[justpete]

I'd forgotten I'd shot 24 12exp rolls of which 8 were developed in Formulary DD-76 a few days ago.

While measuring the 16 other rolls this morning I checked the uniformity across the frame's short dimension and it can be as much as a full stop from center to edge. The density of a given exposure also increases as much a third to a half a stop from film end to start, or outer to inner surface on the spiral.

These numbers hold regardless of presoak or developer or film, with the exception of Arista (Foma) 200. However, the edge to center uniformity of the Arista film is no better than any of the others, it just doesn't 'look' as bad since there aren't any dev artifacts.

Measurements of the DD-76 rolls show a much better edge to center uniformity. Base+fog variance is typically 0.05-0.08DU from edge to center and symmetrical. 'Zone' V measures about a third of a stop, worse case, from center to the top edge and about the same variance as b+f on the bottom edge. The variance from start to finish on any of the 8 rolls is essentially zero, unlike the 16 other rolls.

There are absolutely no development artifacts visible on any of the 8 rolls run through DD-76.

I'm assuming this is due to the minimal developer activity as it soaks into the emulsion. I'm also assuming the slight asymmetrical edge to center density variance is due to the inversion rotation during the accelerator bath. The tank was filled each time with only enough fluid to cover the film in the spiral, or about 250ml in a single reel tank. Agitation was 30s+5X/30s for both bath A and B. Some rotation was imparted but not as much as during the dev tests with the other 16 rolls.

Too bad DD-76 is wayyyy too active for any of the films under test, shot at either box speed or +2/3 stop, at least for an opal bulb condenser enlarger. Times would have to be reduced to as little as 30s-1.5min which just isn't going to work, I think. I haven't plotted and fitted the full data yet, just the endpoints and center so this could change.

Would a much longer presoak with agitation (30s + 5X/30s) make a difference with the non-divided developers? Seems like it'd have to be on the order of 5min or more given the one single artifact-free result with HP5+ in the 16 roll group. Anyone have a recommended time?

[fhovie]

I don't know that I have ever had - under agitation failures - I have certainly had over agitation failures. Sometimes less is more and you don't want the velocity of the liquid too fast or you will have streaks near the spools. - NEVER go under 5 minutes. Always use enough chemistry to keep the developer out of exhaustion.

[Anscojohn]

Use the proper amount of soup for the film in the tank; or even a little more, if possible. And with ss reels, put enough empty reels in the tank to keep the loaded reel in place when agitating. You do not want it sliding up and down in the soup when you invert the tank. My .02.

[justpete]

Tried hanging a roll instead of running it through the Senrac and there weren't any marks of any kind other than the obvious ones from water running down the length of the film.

Took a few of the previously processed flims that had obvious marks or streaks on them and rerinsed in distilled water for a total of 3min w/agitation and then ran them through the Senrac without heat - marks and streaks are gone.

This explains the one good roll of HP5; I remember one develop cycle where I discovered the Senrac heat wasn't on as the drying cycle ended but didn't have time to redo it.

Along the way Edwal LFN didn't help and if anything made it worse mainly with emulsion damage from bubbles that turn out to take quite a bit of force rapping the tank to dislodge. No bubbles using only distilled water so LFN kinda does the opposite of what's expected. And this was at one drop per liter of distilled water dilution, half that called for in the bottle's instructions.

[awaken77]

Regardless of what developer and film I use, I try to use such combination which gives me longer dev time (usually 12-15 min).
Longer is boring, shorter than 10 minutes may induce uneven results, depending on how fast you drain and refill your tank.

For long development time (> 10 min), "regressive" method of agitation may be used:
1st minute - continiously
2nd - every 10 sec
3rd - two times per minute
4-5 - once in a minute
once on 7th and 10th minute,
and then once per 5 minutes
I used this method successfully with highly diluted developers, like Rodinal/R09