Stand developing problem

[graywolf]

OK, I have been stand developing my film in Rodinal 100:1 with good results. Only the last couple of roll scame out over developed.

I think over developed, because I developed a second roll in the same tank that was taken with a different camera months back. I figure it is unlikely that both cameras are over exposing by a stop or so.

My technique is to pour in the developer, invert slowly five times, and then go away for an hour. The only change is that temperature higher than it was in the winter. However, my understanding is that true stand developing automatically compensates for temperature changes. The warmer solution develops faster, but the developing agent in the emulsion gets used up faster, balancing that out.

120 Arista.EDU Ultra 100, by the way.

Over the winter my solutions temps were about 65F, and for these last rolls they were about 75F. I use all solutions at room temperature.

OK, something is not right, but I am not sure what. I guess both my meters may be off, but by the same amount?

[pgomena]

After an hour at 65F with no agitation, how do you know the developer is completely exhausted? If there's still some oomph left in it, there's potential to further develop the film. Yes, at 75F, it should exhaust itself faster, if your assumption is correct. At 75F, you may be increasing the developer's activity enough to squeeze out that extra bit of development over an hour's time. If you assume that each degree of temperature increase/decrease calls for a 4% change in development time to compensate for the change, that extra 10 degrees adds a big variable. You might test this by developing one roll at 65F for an hour, and another at 65F for 84 minutes (140% time) and see if the longer development time substantially increases negative density. Same is same, different is different.

Peter Gomena

[Shawn Dougherty]

Is the film over-exposed or is it over-developed? This should be fairly easy to tell. How do the shadows compare to your usual results?

10 degrees is a significant change.... I would expect some increase in contrast even with stand development.

[Thomas Bertilsson]

Rodinal is slow working, but extremely powerful. It keeps developing and developing and developing. Bop 'til you drop, as they say. You cannot tell with certainty that the developer is exahusted unless you throw fresh film into the solution and try it again. I'm willing to bet that the developer has plenty of activity left after one hour.

75 degrees F compared to 65 degrees is a HUGE difference in terms of developing activity, and you MUST compensate for it when you process film.

[Leighgion]

I'm inclined to agree that trusting that the nature of stand development with "automatically" compensate for any temperature difference is too optimistic.

My own experiences with stand development have been almost all good, but while I'm not draconian about the water temperature, I try always to start it around 70F, give or take. A ten degree swing is huge.

[Gerald C Koch]

However, my understanding is that true stand developing automatically compensates for temperature changes. The warmer solution develops faster, but the developing agent in the emulsion gets used up faster, balancing that out.

Not true. Even at 1:100 there is more than enough developing agent so the developer does not become exhausted. For this idea to work would also preclude a two bath developer from working. There is much less developing agent used per roll in a two bath developer then there is in a normal one diluted 1:100.

So you still need to worry about temperature. This dilution is not all that large and I use 1:50 routinely and must watch the temperature quite carefully. I don't know where these notions originate certainly not from people who have thought things out carefully. It's funny but ideas like this are never prefaced with statements like "Ansel Adams says that" or "Minor White says that", ...

[graywolf]

Well, the point of stand developing is to limit the developer to what is in the emulsion to start. And with the 65 degree temps, my experience is that leaving the film in longer, I have gone two hours, gives no increase in density over one hour. Which led me to believe the developer in the emulsion had been used up buy the end of the hour.

If you agitate at all after that initial agitation, you are moving fresh developer into the emulsion and it is not really stand development. I will entertain the idea however, that 100:1 may be too concentrated at higher temps.

I just scanned one of the edge numbers from that last roll of film. I think it shows the film is overdeveloped. Although the actual images may be both overexposed and overdeveloped, but to solve anything we have to eliminate one thing at a time.



(Crop of full resolution 1200ppi grayscale scan)

[Aron]

My Fomapan 100 (Arista.EDU Ultra 100) frame numbers always come out rather dense on properly developed negatives. Judging development this way can be misleading. Contact printing the negs on the other hand provides a whole lot of valuable information on both exposure and development.

[Gerald C Koch]

Well, the point of stand developing is to limit the developer to what is in the emulsion to start.

There is still an exchange of chemicals into and out of the emulsion even if you do not agitate it.

[Thomas Bertilsson]

Check out this link: http://www.kodak.com/global/en/profe...4017/f4017.pdf

Page 8 has some info on compensating for an increase in temperature, and going from 65*F to 75*F the developing time is cut into about two thirds to compensate for the increased developer activity due to raised temperature. There is no reason to think that standing development would be any different.

Finally - you should not judge on the film's edge markings whether the film got correctly developed or not. Do you print the edge markings, or do you print what's in the exposed film area?