Rodinal APX in colder solutions.

[rob_x2004]

For APX400 I have been using Rodinal 1+50 base 11ish minutes at 20C
Have been having no problems at elevated temps, with actual dev times of round seven to nine minutes.
Things quite a bit colder now with water & weather at 16deg which by the Ilford adjsut times makes about 16minutes.
Getting heavy flat sort of negs which would probably be ok for enlarger but problematic when scanning. I think I recall the cold extended developing being not so much a problem with D76 style developers.
Anyone have any comments / advice wrt extended development times with Rodinal particularly with APX400? Going up the chart, I think I even used to get up round 27-28C and all seemed ok. Coming down seems problematic.

[rob_x2004]

Dust, anyone? Dust? Dust? Anyone? Anyone?

[john_j]

Hello-

I used Rodinal for many years, mostly with HP5+ and Tri-X. I normally used a temperature of 68/70' F (I believe that's around 20' C). I used a dilution of 1:25 with HP5 for 12 minutes (despite what Ilford's specs were) and 1:50 with Tri-X for 10 minutes. I found with Tri-X a 1:25 dilution created too much base fogg, and while they printed fine, the enlarging times were long. A 1:50 dlution corrected this. The Ilford negatives were very smooth but I preferred the Tri-X "soul."

When Rodinal became unavailable here, stateside about 7 years ago I began to use Kodak X-Tol. Not quite as crisp as Rodinal but more to my liking than HC 110, D-76 etc. Rodinal has since become available again but it's very hard to find so I continue to use X-Tol.

For you, I might advise to try a dilution of 1:25 or heating some water to mix with the cooler water. Perhaps I should have just sent this one sentence!

Best,

[rob_x2004]

Yes I went back to heat baths for the next batch, but I am wondering what is going so far astray below 20C. It seems some factors are much more time dependent than temp or concentration dependent, and that you just cant afford to follow conventional thinking. If I had to work at lower temps then I imagine keeping the times short and increasing agitation, which woudl be a heap more testing for little point. Someone who knows their stuff well probably has the technical at their fingertips.

I got into the habit of working at ambient temps because in hot weather I dont have an airconditioned room with my gear in it. Ice baths were impractical and there would be a temp rise from the heat soak of the kit and with agitaion. Like I said in hot weather it works fine, I didnt really think it through and I got caught out in the cold. Lesson learned I guess.

[john_s]

I remember reading (but I can't remember where) that Rodinal actually works better at a lower temperature. I remember 65degF (approx 18degC) being quoted. At a longer dev time, of course.

From the old Agfa pdf file about film developers, and extrapolating from the graph which goes down to 18degC, it looks like they would recommend 18min at 16degC for gamma=0.65 which is about what you're getting at 11min at 20degC (assuming your agitation is the same as theirs).

Maybe 16degC is a little too cold, but extending development would be worth trying if you like Rodinal at your other higher temperatures.

[rob_x2004]

No it is defitely wrong. I got a flat clumpy black so dense it really curled the negs. What I was getting at higher temps, was a thinner lively neg with fabulous contrast and lovely flat. They were so clean they looked like Scala. I may be able to retrieve something from the cold water developed negatives using an enlarger, or if I can get a pass, CERN might be able to shoot something through it but hte scanner is well outside its comfort zone.

Might be time to belt out a roll and try it again at 16C, bring its time way back and increase agitation jsut to see what is going on. Maybe rodinal likes that, find the time to give optimum negative density but keep it honest in the cold with agitation?