View Full Version : Trading time for temperature?

Marko Vrabec
27-Dec-2008, 05:50
I just started developing BW film on my own. It's cool!! I use Adox CHS 100 4x5", developed it in ATH 09 (a Rodinal clone), in Jobo Expert 3006 tank on a Beseler base at ~25 rpm, reversed the drum each minute.

For my first run, I used development times as suggested in the Digitaltruth database. All went fine (I suppose in no little way thanks to the forgiving nature of the materials used), apart perhaps from noticeable grain visible in sky portions of the test shots, but that's Rodinal I guess. For now I'll stay with what I have.

I find the development time a bit too long, it's 13 min for normal develompent at 1+40 dilution, at 20°C. Particularly the N+1 time, 18 min, is a bore. If I increase the development temperature and/or decrease developer dilution to speed things up a bit, will there be any negative side effects? (If I recall correctly, increasing both dilution and processing time has a side effect of making grain even larger, but I'd be doing just the opposite.)

Bjorn Nilsson
27-Dec-2008, 16:42
Ilford and others have graphs and/or tables which gives you the proper adjustment for time vs. temperature.
It's fairly safe to say that if you go up to say 24°C and reduce time from 13 to 9 min there will be no noticable change in grain.
I have attached a pdf-table from Ilford, where you can find the correct adjustments. Within the temperatures given in the attached table, while I "never" go further than 24°C, it's fairly safe to assume that grain-size is more or less the same regardless of temperature as long as you compensate the time accordingly.

I take it you know that if you print these negatives they will also appear very sharp, which is the "other side of the coin" with Rodinal. By the way, how have you spotted the grain? Strong loupe? Big enlargement? Scanning?


Bruce Watson
28-Dec-2008, 07:06
My reading of Grant Haist's two volume tome Modern Photographic Processing, and Henry's Controls in Black and White Photography indicate that graininess will increase somewhat with an increase in processing temperature. But it's at worst a minor effect, especially when compared to film choice, developer choice, and the density range you develop to.

For a given film/developer combination, your biggest control over graininess comes from how much density you develop. In general, you want just enough density to let you print (or scan) easily, particularly the print's highlights, and no more. That's because with more negative density you get more graininess and the possibility of "blown out highlights" with no gain in print quality.

Len Eselson
28-Dec-2008, 07:40
A characteristic of Rodinal (unlike many developers) is that grain is reduced as dilution is increased. Try it at 1:75 or 1:100 if you would like a finer grain. I regurlarily use Rodinal at 1:75 on TMAX (CombiPlan tank, 20C, 11.5 minutes for N) and can barely see grain in my focuser when the enlarger is set for 4X (16X20).

Len Eselson

Marko Vrabec
28-Dec-2008, 09:34
Thanks for all your responses. (Particularly for the Ilford time-temperature table, Bjorn; it is much more useful than the graph available at Digitaltruth.com).

In the meantime I did some more searching on the net and found out that the distributer of Adox films doesn't recommend developing at temperatures above 20°C due to high sensitivity of the emulsion.

I also found dilution/time conversion table for Calbe R09 developer (same thing as APH 09). It suggests x 0.5 reduction in developing time when dilution is reduced to 1+20, thus giving me 6:30 min instead of 13 min. I tried this with my last set of 3 test negatives, and the results are OK, the negative contrast falls right between the N-1 and N+1 examples developed previously in normal 1+40 dilution. Per Len's suggestion I will also try 1+100 dilution, but have to first shoot some more test frames.

WRT grain: I was aware of the sharpness-grain tradeoff of Rodinal; I choose to start with APH 09 mainly because it is recommended by Fotoimpex for the "old-style" Adox emulsions, and also because it has long shelf life and is very economical. Nevertheless I was surprised to see noticeable grain in scans; grain of Adox 100 scanned at 2400 dpi on Epson 3200 is comparable to what I see on 35 mm slides scanned with Coolscan 5000 at 4000 dpi...

I enclose a sample, a 2400 dpi unprocessed crop at 100% size. Graininess is also noticeable on a light table under 4x loupe. Is that normal?

I will be printing with Inkjet.

Bjorn Nilsson
28-Dec-2008, 11:27
The grain you are getting doesn't seem too bad. Now, Rodinal is known for giving very pronounced and sharp grain, so if you wouldn't have grain in your scan, the whole scan would be out of focus.
If you plan to try 1:100, see to that you have enough concentrate to begin with. At those dilutions it's easy to use too little syrup so that the dev will exhaust before being ready. That is, mix more than the minimum for the 3006 drum.

As you are scanning and printing inkjet, you will benefit from another developer, as Scanners doesn't like grain. I use Pyrocat HD (a staining developer) will suit you better. (You can find Pyrocat at www.lotusviewcamera.at .) Now, there are many developers which are more suitable with scanning, so almost anyone of them will do. Do a search for e.g. "scanning developer" and you will find many nice tips.