maintaining chemical tempature

[brian steinberger]

I've been processing my own film for sometime now, and I've been using 72 degrees as my standard processing temperature. I use tanks with hangers for my 4x5 black and white. What I do is fill a plastc container with very hot water, and then put each tank (dev, stop, and fix) into this container to heat them up. Since my basement room temperature is 60 degrees this warms up the solutions. I usually warm them up until they hit 75 degrees, then I turn off the lights and unload the film, assuming that by the time I unload the film onto the hangers that the solution will be appoximantley 72 degrees. I don't think that this method is totally reliable. There has to be a way to maintain a constant 72 degrees during processing. That is my first question. My second question is: is the developer the only solution that is very temperature critical? The stop bath and fix don't have to be exactly 72 degrees, do they? Mine is usually between 70-75. Same for the rinse. Thanks alot!

[David A. Goldfarb]

As long as the stop and fix are pretty close to the developer (within 5 degrees or so), you should have no problems. For most B&W work, you can probably get away with about 2-3 degrees of drift in the developer temperature, though for T-Max films, it helps to be a little more precise. There are temperature control units that you can use in conjunction with a pump like an aquarium pump to keep the water jacket temperature right where you want it. I think Freestyle sells an inexpensive model.

[Tony_5130]

I am no expert but apply the same logic as you. As far as I know, the only critical step is development. The stop bath does what it says regardless of temperature, and the only thing that can go wrong with the fixing stage is insufficient time. I would think it was nigh on impossible to over-fix anything. I fix my negs, both colour and black and white for at least twice the recommended time. Back to the subject of development temperature, I invested in a small fish tank heater to keep the water in my bucket warm.

[John Berry ( Roadkill )]

The only temp that is critical is developer temp as was stated earlier. If you can keep your chemicals in a large water bath container they will keep more constant temp. Why are you developing so high of a temp? My developer temp is within + /- .2 degrees. If your shooting zone and expect values to be where you place them. Your temp can't be approximatly there. It has to be there. Consistancy is the key to everything. 1 degree can make a difference in what you get. I agree with others that you can have a five degree difference in the other chemicals, but developing is the whole ballgame. Consider the effort to develop properly, compared to the task of trying to get a good print out of a substandard neg. It's a penny for your thoughs, so that's my 2 cents. Rember my opinion is only worth what you paid for it.

[Dave Moeller]

Adorama sells a submersible heater for somewhere around $100...if you can get a water bath to near your target temperature then you can use something like this to hold that temperature throughout the development cycle and just keep your development tank in the water bath.

As others have mentioned, temperature is much less critical for the other chemicals, although you don't want to vary the temperature too wildly (for example, you don't want to use 40F water for rinsing) as sudden and extreme temperature changes can cause the surface of the film to expand or contract at a different rate than the film base, leading to cracking of the film surface. In my experience, +/- 5F is very safe for stop/fix/rinse...but you really want to be sure you're keeping your development temperature consistant and reliably the same from batch to batch.

One other thing you might consider is adding a space heater to your darkroom. (The heater itself should be available for a whole lot less than $100, but energy costs over time will bump up your cost...heating the air every time you develop will probably be more expensive than heating a tub of water with a submersible heater.) If the air temperature is near the target chemical temperature, the water temperature is much less likely to fluxuate during development. I standardized on 70F for my work because my kitchen stays at that temperature pretty much year-round, and that's where I do my development.

[Eduardo Aigner]

Tony, you should not over fix your films or prints. The residual fixer will be very hard to wash out.

[Tony_5130]

Fair point, though I have had problems fixing T-Max where a pink tinge is apparent over the entire negative surface. The only way I found to get rid of it was to over-fix. I am open to suggestions on this if you know why it occurs.

[George Stewart]

To get rid of the pink/purple ting on TMax negatives, use hypo clearing agent. I would not recommend fixing TMax more than indicated by the directions.

[Neal Wydra]

Dear Brian,

Consistency is more important than anything else. Once you have a technique that gives good results and that you can repeat, there is no need for concern. One of the benefits of your system is that the solutions will cool together so you're never shocking the film from bath to bath.

Neal Waydra

[Don Wallace]

FWIW, I invested in a second hand Jobo and I love it. A CPE with the lift is not all that expensive - I got mine for about $200 -and it sure makes life a lot easier. Easy to use, cleanup is easier, results are consistent.