Film dev: are dilution and time proportional?

I have been experimenting with slow films lately (Maco Ort25 and Efke25) and my developing times are getting short. I overcooked some negs developing them for 2:45min per bath in Thornton's 2 bath developer. Also for example Digital Truth suggests a short development time with other developers for Ort25 such as Rodinol 1+25 for 4 min. So, here are my questions:
1. Should I be worried about uneven development with such short times?
2. Are developer dilution and time proportional? If I double the dilution can I assume double the time as a logical next step in searching for better negatives?
3. Is a more dilute developer with more time likely to result in more evenly developed negatives?

Many Thanks,
James

I believe Kodak says times under 5 minutes may be a problem. I shoot for times in the 8-12 minute range.

I wouldn't assume that time and dilution are inversely proportional. Do a test before risking any negs you care about.

If they recommend Rodinal 1:25 for 4 minutes, I'd try 1:50 for 4, 6 and 9 minutes.

As Fred Picker would have said, "Try It!"

its not as perportionate as you would thing, since the longer the film develops, the less of an effect something say 30 seconds has on film. For example if you normally develop at 4 minutes, 30 second deviation can mean a full stop or so, where as a 30 second offset at say 8 to 10 minutes might not effect it as greatly. So the more the dilution, the longer the time, but not to the sense of double time. It cannot hurt to take a small cut of a strip and test it.

Times on the manufacture box and on sites such as digitaltruth are helpful starting points, they're not nessarily etched in stone, and one person result's may be another's nightmare, so it helps to use the starting point to formulate your own recipes.

With Rodinal I'd say yes, dilution is pretty much proportional.

Now with Efke 25 rodinal 1+100 should give you a time around 10 miutes for EI25.
Me guesses that time should be Ok for Maco Ort25 as well.

As per what kb says, I prefer working in the 10 -15 minutes range, since it allows a small margin for error (30 secs is 5%) and can be used with agitation once every minute or once every 2 minutes. Which increase the shadow detail

For Maco ORT 25, Rodinal 1+100 for only 11 minutes, gentle agitation each minute (EI of 16 or 25 more or less), you will get negatives that should print nicely on grade 2. I have some decent examples of such results in my gallery.

For Rodinal dilution/time factors (from R09 handout):

1+20 0,5
1+40 1
1+60 1,5
1+80 2
1+100 3
1+150 4
1+200 6

With more diluted Rodinal you gain more film speed (thanks to compensation), finer grain, smoother tones and more pronounced edge effects. Too short development times are generally not recommended.

James, you're talking about a divided developer, where the amount of liquid the emulsion will absorb is more critical than the development time. So, if your film's emulsion swells easily the film will be further developed than if you have a film with an emulsion that doesn't swell so much. I guess that temperature could control the amount of swelling for some types of emulsions. Lower the temperature of the 2 developer baths, prolong the time in each bath and experiment. 2min 45 is not so short for a divided developer, though. Is it a staining one (pyrocatechol) ?

Thanks for the responses and sorry for the slow reply (a storm blew through yesterday taking out the phone line with the roof of our woodshed). Good to see that there are still some faithful Rodinol users out there. I may use it if my attempts with the 2 bath fail.

George, its good to know that I can try shorter times with the 2 bath. These films should have thicker emulsions, the Efke at least… I’ll try 2:30 and shorter in each bath. My understanding is that the 2 bath developers are less affected by temperature. I use the 2 bath as a ‘travelling developer’ for that reason-- I can leave the thermometer at home and drop out one of the variables in developing when I’m away from the familiar setting of my darkroom. The other benefit is that I just use the stock solutions and you can leave some of the graduated cylinders behind (though I was thinking about diluting it to increase developing times but as I said I’ll just try shorter times and see what happens).

The Thornton 2 bath is not a staining developer, it’s a variation of Stoeckler 2 bath. I found most of my info on it at the following web sites and in Thornton’s “Edge of Darkness.” I’ve come to really like it for FP4+ and Pan F which is one reason I turned to it for the slow films

Dead Link Removed
Dead Link Removed
http://www.largeformatphotography.info/twobath/

Many thanks,
James

Yes, I guess that they're less affected by temp changes, since the development should go on until the solution absorbed by the emulsion is exhausted... but this must be true for minor temp changes, not huge ones... You can play with the dilution (alkalinity) of the second bath, too... it will probably affect the development time, although I don't think it'll be proportional.

The late Barry Thornton used to make DiXactol, an interesting though difficult to use staining divided developer, too. It was based on a Pyrocatechin formula, if I am not mistaken.

Yes, I think you're right about that. I've never tried DiXactol but I am using Prescysol, a Pyrocatechin developer that may be a descendent formula of DiXactol (Peter Hogan sells Thornton's developers). All of my large format and half of the rest of my film is developed in Prescysol. Whatever's left gets dunked in Thornton's 2 bath. Now that I think about it I've probably taken them because in one way or another they allow me to be sloppy in my exposures or developing and still end up with something that is printable.
You've used DiXactol or other pyro developers much?

With the Efke and Rodinal, you will find that extending your development time through dilution has several benefits. This film seems to have a hard contrast ratio, meaning that it is very easy to blow out the highlights and sometimes very hard to eke out the nuances of shadow in very brightly lit situations. I use the film with longer exposure times on days that there is gentle light or are overcast. Don't be afraid to stop way down, use ND filters, and considerably extend the exposure time. KB25 has very little reciprocity failure, and is consistent with FP4.

Going to a 1:100 dilution of Rodinal and also reducing the number of inversions will help you to add more local contrast to the detail of the negative. I am at 30 minutes for this process (68F), which essentially is a slightly modified stand development. Agitate for the first minute (after a full 2 minute prewash), one inversion at 15 minutes, and drain at 30. You do not state what format film you are shooting, but 120 and 4x5 have both seen good results even at 45 minutes with no drag. The larger format in Rodinal seems to have the best result. There are a number of photographers here who advocate 1:200 in full stand, but I have not tried that.

I note that you do not give the speed you are rating the KB25 at. For shorter conventional development times this may make as much as a full minute difference in the process when rating at half (12) in the 9-10 minute range versus shooting at box speed. With pour times and stop delay this can change your outcome by nearly a half stop or more. By stop delay, many of us have decided that a water bath stop is best for this film (pinhole reduction). Hence, depending on the Ph of your water, there is a delay factor in achieving full stop of the developer. Cutting the rated speed also seems to improve the overall tonality and detail of the film.

Hi Patrick,
I'm shooting both the Efke and the ORT25 at 25 since I get full speed out of the 2 bath and Prescysol developers. I've shot one rolls of each and got full shadow detail but blew the highlights. Thanks for your detailed description of your method. You might convince me to try Rodinal again after all. I have a half opened bottle that I haven't used for 18 months or more.
Best regards,
James

There are a few threads on here James that detail results and methodologies for stand and semi-stand development. Not to start one of the holy temple of Rodinal wars, but my experience has been where this developer truly comes into its own, along with slow films. The beauty of this method is in the local contrast, and expecially those situations that would otherwise muddy or confuse into a medium grey fine detail. This is the lower light situations.

When I first tried KB25, I was looking for a holy grail that would replace Pan-X. No cigar, any more than I found Bergger a replacement for Super-XX. It is however a great film. Being orthochromatic, it behaves rather difficult with some filters, especially the red. There are threads that detail this as well.

blackmelas said:

You've used DiXactol or other pyro developers much?

Click to expand...

No. I tried DiXactol, it gave some really good results with Agfapan (GREAT edge effects) but wasn't any good with other films I tried it on. It was a PITA to use and so I gave it up. Then Thornton stopped producing it, then he passed away. I always tell myself I should start using Pyro, but I haven't yet started...

Again many thanks for all the replies. After a couple more tests, Thornton two bath at 2:15 in each bath worked well for the ORT25c. After the first print session with them the negs printed only average, not at all like the snap I'm getting with FP4+ and Pan F in the same developer. So I'll keep trying to see if there are situations were these films and developers should marry well.

I also did clip off a section of 8 frames of the ORT25 to try the Rodinol semi-stand mentioned by Patrick. Unfortunately, I picked it up about 5 minutes in and accidentally gave it 5 inversions (I was fixing a roll in another tank at the time). They came out contrasty but printable. I'll give the ORT25 and the Efke a try again next time in the Rodinol.
Best regards,
James

P.S. I see others marking their posts-- This is my 300th! WhOOOOOOpiEEEEE!

James, I have never run 35mm in Rodinal, which I gather you are using for your testing. From some of the threads on the developer here, we are led to believe that Rodinal, and stand development are not optimal for that format. From my own trials I have found that the overall performance of the stand method increased proportionally to the size of the film format; 4x5 is absolutely stunning. Perhaps PE or Steve Sherman could jump in here as to the reasons why. More halide coverage?

Anyway, here is a good thread on the subject:

(there was a url link here which no longer exists)

I had heard rumor that the ORT25 was supposedly a good sub for Tech Pan. Any comments?

I'll check that thread out, Patrick. Yes my first venture into Efke were 35mm, mostly due to its economical price in bulk rolls. I figured I'd have fun seeing if I liked it. I may grab a few rolls of the 120 soon and continue with the Rodinal. At least I can finish the bottle that way

I couldn't tell you about ORT25 and Tech Pan. I never used Tech Pan.
Thanks again,
James