Rotary processing B&W film - dilutions and amounts

[M Carter]

Been very happy with rotary for 4x5 sheets; 15ml DD-X + 135ml water for 1+9, looks great, saves a lot of developer.

But that's been one sheet at a time; my tank will hold two, so I need to test for matching the density between one neg and two negs.

Two sheets with 15+135 (of course) shows very weak development, there's not enough developer in the can for two and the dev exhausts.

So for two sheets, would 30+270 get me in the ballpark? (My tank can do 300ml without overflow). Or is the additional depth of liquid (and thus the film being submerged for 2x the time) going to change development time?

I know I'll need to test to dial this in, but I've burned through a lot of film getting happy with my one-sheet time. Just looking for a starting point or any advice to dial it all in.

 

[Craig]

You're mixing 1+9? The reccomendation is 1+4. There was a discussion about the minimum amount of developer needed quite recently, and I think the result was 50ml of concentrate is needed per 135/120 or similar amount of film.

That would suggest the minimum amount of concentrate is 12.5ml per 4x5 sheet, so 30 +270 should work well. Double the film, double the concentrate and keep the overall dilution the same. The change in liquid level should have little effect.

 

[M Carter]

You're mixing 1+9? The reccomendation is 1+4.

There's been so much chatter and discussion of DD-X 1+4 vs. 1+9 over the years - my personal belief is that Ilford may have a "profitability" motive mixed in with technical issues, as DD-X is a fairly pricey product with a short shelf life, so I started testing. In my experience (test still life lit with strobes and metered for all zones, so repeatable through a testing day) was that DD-X at lower dilutions (1+7, 8 or 9) requires (of course) extended dev. times, higher temps, or a combination - but unlike Rodinal/etc., tonality and sharpness remain the same if you get dev. times for highlight density dialed in (based my results with test prints at grade #2.5, print exposure time based on minimum time to hit max black on the leader or 4x5 edge). The Massive chart includes some 1+9 times, there's sometimes a little clamor for Ilford to address 1+9 in their literature.

Maybe a densitometer would show some subtle curve changes, but in the real-world, all good with reasonable dilutions.

But beyond that, thanks for the scoop regarding quantity. I've blown through a fair amount of 4x5 with various tests this month, I'm kinda "damn it, I need to go actually shoot something now!!" so I have ten sheets exposed last night, with a model on a room-sized set I spent the last 6 weeks building. I'd rather soup 'em two at a time! I've got a 1-off neg as a baseline for comparison.

FWIW, this is my general test setup; I don't own a densitometer and am happy with "real world" testing; the test chart shows me half stop increments, so I can dial in N, and plus/minus times in half stop increments in an afternoon. (I get my nice Mrs. in there for some skin tones, she's a trooper). I've got texture in her dark knit sweater and texture in the white styrofoam (vs. blown-out-white), so it's a "works for me" capture of wide tonal range and I can pop the contrast easily in printing if needed. This is Delta 100, ISO 80, Rodinal 1+50, regular tank development vs. rotary:

 

[MattKing]

That is a fairly low key test subject. If you are going to test for capacity, you need to use a subject with lots of mid-tones, high mid-tones and highlights - something that will result in a negative that has lots of dense areas. Otherwise, you won't be challenging developer capacity.

I was glancing through the scans that I have conveniently at hand to see if I had some good examples to illustrate what I'm talking about. That effort brought home to me that I seem to prefer dark and moody .

 

[MattKing]

FWIW, the product datasheet's capacity information does indicate that Ilford's recommendation for one-shot use is 15 ml of concentrate per 4x5 sheet. And of course, Ilford's material recommends 1 + 4, not 1 + 9. That is in contrast to Ilford's recommendations for other developers, which in at least some cases do provide for a variety of dilutions.

 

[M Carter]

And of course, Ilford's material recommends 1 + 4, not 1 + 9.

Yes, I went into that in my reply above, in short many people have questioned "why 1+4 and no dilutions?", but many people go 1+9 with extended times/temps. In the last few years of printing from DD-X negs, I just don't see any tonal differences, though my testing has been "dev. the same setup to the same visible density on a print and compare the prints" vs. using a densitometer. I just don't see a real-world difference between dilutions. Certainly there could be things a densitometer would pick up, but in my real-world use, it's all good and no tonal shifts like one gets with Rodinal dilutions.

I'm slogging through a bunch of 4x5 negs today that are extremely high-key, half the image is blown-out white BG (I'll be compositing these in the enlarger so it's sort of "built in masking", and so far so good. 1+9 with adequate time and the proper amount of developer has never failed for me as far as high density goes.

 

[MattKing]

I referenced that peculiarity in the Ilford datasheet because it may very well be the case that their capacity recommendations would be affected by the change in dilution, even when taking into account the increased total amount of dilute solution.
In fact, that could be the reason that they don't recommend 1 + 9 - the capacity decrease is a problem. Or perhaps there is a problem with more dilute developer oxidizing more quickly. The collection of potential reasons is large.
In any event, starting out with at least the minimum necessary amount of concentrate before you dilute it is important, and 15 ml doesn't seem to be enough for two sheets of 4x5.

 

[M Carter]

Yes, I mentioned that in my initial comment, even tested it - been covered as far as "15ML doesn't exhaust with one sheet but does with two". My only question was if going to two sheets and doubling the 1+9 amount in a rotary tank would be expected to give similar density, or does the greater capacity (meaning the sheets are submerged longer than in a 1-sheet situation) make a difference. Just wondering if there was some specific behavior to take into account.

I just developed 2 sheets with 30+270; to my eye they match my one-offs, but it should be quite apparent once they're dry and I pull a quick test print. (My question was similar to something like when one switches to rotary processing and wonders about effects of continuous agitation, is there something "everybody knows" that I don't yet? Couldn't find a specific answer with general web searches, Craig suggested I'd see no effect. I'll know in an hour or two if there's even a subtle shift in density though).

 

[Craig]

A Jobo doesn't have the film continually immersed in developer, but presumably for the fraction of a second that the film is wet, yet not immersed, there is no localized exhaustion of the developer. As long as a rotational speed is sufficient to prevent exhaustion, I can't see not being immersed a problem.

In a Jobo tank the film is out of the developer for about a second, that clearly isn't enough to exhaust the developer layer left on the film. I can't see being immersed vs not making a difference in those short times the film isn't immersed. I suspect the additional agitation more than makes up for it, as the typical recommendation is to shorten rotary developing times compared to continuous immersion, not lengthen them.

 

[M Carter]

Thanks for your thoughts, and "the proof's in the pudding" as they say (well, let's say "in the pasta"., I'm not a big desserts guy).

Ran a two-sheet batch with 30+270, test prints are drying but it looks dead-on with the 1-sheet batches, so I think your thinking is correct here. There are a couple areas in these shots where gray ramps off to stark white, so as far as eyeballing-it goes, when the tests are dry I'll be able to see even a slight difference in the sizes of those grads.

(Reason I'm doing this stuff is I'm compositing these shots in the enlarger, so I push some BG areas to full white while trying to avoid flare. When the set is built I run quite a few single sheets to see how exposure and development are working for this oddball stuff, but when the model gets here, I shoot at least 10 sheets and while I'm happy doing 2 at a time, singles would just be too long for me).

This is what I've been up to, previous completed project, model is seated on a life-sized set that extends to the foreground, but the background is a scale model about 10-12" high. Composited on canvas coated with FOMA emulsion, about 30" high, then tinted with oils. Kinda obsessed with it, but damn, this current set build was 6 weeks and three bags of plaster. Then I have one shot to get it right with talent here, so lotsa paranoia.