Optimal processing temp. for B/W

gedra · Jan 13, 2009

Hello: I recently returned to film after 7 yrs. in the digital wasteland and am developing 120 B/W for the first time in decades - using FP4 in HC-110. Here in AZ 68 degree tap water for temperature bath and film washing is easy to find in Jan., but will be tougher in July. Can I move to 72 or even 75 degrees without sacrificing quality? Ilford recommends 68, but I've read suggestions that modern films do better at higher temps. since they are wet for a shorter length of time. Thanks in advance for your help.

fschifano · Jan 13, 2009

No problem raising the temperature as long as you compensate for that rise with shortened development times. The only problem I see for you is the use of HC-110, dilution B. Development times with this developer at this dilution are pretty short for a lot of films. Shortening development times could get your processing time below 5 minutes which is generally regarded as the safe lowere time limit to insure even development. You could, of course, dilute the developer more, thus increasing the time needed to reach your target contrast index. Sometimes, data is a bit hard to find for higher dilutions of HC-110, and in those cases you will need to do some experimentation to find your ideal time.

Ilford has a very good time/temperature conversion chart on their web site. Find it here: http://www.ilfordphoto.com/Webfiles/2006210208211880.pdf. Alternately, you might prefer to use a slower working developer like D-76 or ID-11.

Ian Grant · Jan 13, 2009

Here in Turkey it's not to cold in the winter, during a cold spell tap water is 18-19°C so I process films at 20°C (68°F), but in the summer temperatures can rocket at times to over 40°C and so I process at 24°C (75°F), there's no difference in quality, obviously I adjust the dev times.

Ian

gedra · Jan 13, 2009

Thanks for the responses. I'm diluting HC-110 to 1/49, so my development time would drop to 7 - 8 min which should be OK.

fschifano · Jan 13, 2009

Perfect. You seem good to go.

dpurdy · Jan 13, 2009

Within reason I think the most important thing is to find the temperature that is easiest to be consistent with over the course of a day.

George Collier · Jan 13, 2009

Also, maintain the same temp all the way through processing and wash.
FWIW - I use HC110 at 1:60 all the time, just for more control.

Kevin Caulfield · Jan 13, 2009

Here in Australia, I need to heat the cold tap water slightly in the cooler months to get to 20 C (68F). In the warmer months like now, I develop at around 22 or 24 C, and in-between, the cold water is very close to 20 C. You're fine at around 24 C, especially with developing times around 7- 8 mins.

Kevin Caulfield · Jan 13, 2009

One other points is that you can use a "controlled drift" development. For example, you may cool your water to say around 23.5 C, knowing from your experience that it will drift up to 24.5 C during the development, giving you an average of 24 C.

rcoda · Jan 13, 2009

I do all my TMax and Tri-X at 75 deg here in Scottsdale. Yes, the times are shorter, but as long as you are consistent, no problems. Also, use distilled water. In the summer, you can use ice to keep the temp down (I use a Jobo, and keep two Jobo bottles of water in the freezer at all times for tempering).

Optimal processing temp. for B/W

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