Temperature control in C41 - manual process

[ashokgoyal42]

How does one control the temperature for the crucial developer process in C41?

I've been heating the Patterson film holder so that the heat doesn't dissipate but despite that when I pour the developer at 39 degrees - it shows 37 within a few seconds.

Should I set the developer at 40C and then let it fall to 38? Any ideas?

[Ottrdaemmerung]

Use a water bath. Fill a container (like a styrofoam cooler, a plastic bin, or your sink) with warm water until it comes up to about 2/3 the height of your Paterson tank. During the developing process, between inversions, let the tank sit in the bath so that the chemicals inside don't have a chance to cool down.

[hpulley]

I use a simple Rubbermade container water bath AND a 1 minute pre-soak. I pre-heat the developer and blix to 39C and also prepare a pre-soak (same volume as developer) at 39C. This way the tank is already close to 39C before the developer goes in. Using a Paterson plastic tank with the pre-soak and keeping it in the water bath except while inverting I don't lose temperature over the 3:30. The blix is not as crucial, can be even warmer like 40.5C as it goes to completion. Rinse water again isn't as crucial, 35-40C or so. Don't let it get too hot though, you can melt the emulsion at 50C.

[Diapositivo]

Even better, two 30-seconds pre-soaks (at treatment temperature) rather than one. The water of the first pre-soak cedes heat to the film and tank, and cools a bit down (somehow half-way between film temperature and water temperature, I guess), the second pre-soak sets the film further near the right temperature.

[hpulley]

Another thing, if you're doing more than one tank in a row, keep the developer and blix bottles in a bucket of 45C water or so to keep it at 40C until you use the next tank. If I could figure out how to load 2 120 films on a single 120/220 reel I wouldn't have to do this but as it is I often have 3-4 120 rolls to do and with only 1L of solution I need to do 2 batches. I need to practice with film and tape in the light to see how to do it, I can't seem to get the second roll to stop sticking when it's been taped...

I suppose if I got a 2L solution or bought some one shot Kodak Flexicolor kit bottles then I could get a bigger Paterson Super System 4 tank and do 4-5 120 rolls at once in their biggest model.

[ashokgoyal42]

Thanks everyone. Pre soak is a good idea - that should help reduce the temp drop significantly. Also good is keeping the Patterson inside the water bath in between inversions.

[Athiril]

45c presoak in a plastic processing tank, pour in developer when its up to temperature after draining tank.

[Mike Wilde]

If I could figure out how to load 2 120 films on a single 120/220 reel I wouldn't have to do this.

I load on Paterson reels. I find the white newest version of plastic works best, as it seems to be the slippiest, but all will work.

Load the first film. Once it is past the ball bearings, place a thumb on the end of the film, and while continuing to walk the reel back and forth, you can feel the film continuing down the spiral. A very gentle pressure may be needed to push the thing along.

At some point it will not spiral in any more, and you will fiddle for a second or two before you are sure this is the case. This is normal for me, even after doing this for quite a while.

I then begin to load the second 120 film. I usually take the backing paper off first, but be sure to do so for this second roll. I hook a pinky finger of my 'still' hand into the film to keep it from getting too close to the guide path and getting stuck. When I feel the roll to be loaded disappearing, I slow down on the reel rocking, and stop just after I feel the film get onto the spirals.

I would recommend pratciting with scrap rolls first, but it does reliably work for me.

[hpulley]

Interesting. Too bad I don't have any wasted film to practice on. Next one I respool onto 620 and shoot through the Tourist I could try as the first roll I suppose, it will already have had a fairly rough life...

[jm94]

When i did C-41 i found it easier at ambient temperature, increasing the times. I used the nova press kit, which also includes a table. I find the chemicals alot more tolorent at 20 - 24C than higher. 24C i usually develop for 7:30 minutes. Blix isnt as critical as the developer, i prefer to use a stop bath also. Tetenal chemicals (2 bath) seem to hold up well at 24C for me aswell. I use tank processing. The rollei (agfa) and Fuji i cannot comment on. You might find it easier to go down the room temperature (20C) route, if you do not mind increasing the times. Experiment