Patterson Tank Cooling Sous Vide

I recently started to develop C41 using a sous vide stick, and I've had all kinds of interesting (learning) experiences.

One thing, on the path to consistency, I've noticed is that the Patterson tank is some how cooling in the tempered bath. Once the chemicals reach 102, adding it to a pre-washed @ tempered temperature, the tank seems happy to loose 1-2 degrees, with in the first minute- I have to kick up the sous vide to around 108 for the tank to stay at 102 for the duration.

I can't imagine inversion agitation (5 second max) is causing the tank to loose heat despite, but maybe this a well known experience with sous vide? The water in the bath comes up to the shoulders of the tank, so I don't think this is the issue.

Sounds like your pre-wash or dry (inside) tempering is too short, not getting the tank and film up to working temperature. You gain nothing by turning up the sous vide anyway -- first, it takes a long time (compared to the C-41 process) to bring a reasonable size bath up by even 1F, and second, because it's thermostatically controlled, it'll heat whenever the bath is below the set temperature. Judging by the dimming of the room light, mine kicks on and off a couple times a minute even when the display hasn't wavered from my set 102F.

Depending on the ambient temperature in your darkroom, the tank could also be losing heat to the counter top or the room air (by evaporation as well as conduction) when it's out of the tempering bath. That's why I use a drift-through setting of 102F rather than expecting to keep the bottles, tank, and all contents at precisely 100F. I don't even normally stand my tank in the bath; unless the solution inside is deeper than the bath, the tank will float, and a Paterson tank will not float upright: it'll tip, letting your solution out into the tempering bath and water into the tank, as well as leaving part of the film above the solution even with the inversion cap on (I don't agitate by inversion in C-41, in order to limit oxygen exposure for my replenished color developer).

I use a slightly crazy, yet so far successful, method for dealing with the patterson tank temperature:

I ignore it.

I heat the chemicals to 103, (assuming they'll lose a degree or so when I pour). That includes my bottle of filtered water that I use for the pre-soak. I load the film into the tank at room temp (around 76F), pour in the pre-soak, and follow the directions. I don't bother pre-heating the tank. I do all my agitation outside the water bath, and the tank stays dry the whole time. I do use glass bottles, so they take longer to reach temperature, but they'll hold temperature stable for a longer period of time. I also dry each bottle as I remove it from the water bath, but that's more neat freak than thinking the water on the outside will significantly contribute to heat loss.

I've developed Portra 400 and Fuji 400H this way so far, with no problems. YMMV, contents may settle, I take no responsibility, bla bla legal bla... but as I say, it's been working for me.

@grat you just described the Cinestill C41 kit instructions, so you're not crazy at all.

Вormental said:

@grat you just described the Cinestill
C41 kit instructions, so you're not crazy at all.

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@Bormental I heard you had some issues with CInestil C41 and I'm having similar, could you link me to that thread please

@grat those are indeed cinestills instructions

@Donald Qualls
Well actually I set the sous vide to 107 initially. When the water turns to 102, I pour the cooked prebath into the Patterson. And leave it in the bath, I Let the dev reach 105, and bring it out to cool to 103. At this point I swap the presoak for the dev, and start sweating bullets, praying to the C41 gods, etc.
The water is very much at 107-108

Get a large bucket for your water bath, more mass, less change in temperature. Make sure your chemistry bottles are sealed, throw those in. Let the bath stabilize at 103 or whatever you are processing at and then simply immerse the entire Paterson tank into the bath with the flexible cap off and sink the tank to the bottom of the ocean and let it sit for 3 or 4 minutes. Don't shake it just make sure it's full of water. You may see a small cloud of pink dye, but that won't hurt anything.
When ever you are really ready, dump the tank and begin. Heck that tank could probably sit for a half hour, wouldn't make any difference. The beautiful thing is if you get a Paterson tank at the prescribed temperature, it will hold it nicely.

RoboRepublic said:

@Bormental I heard you had some issues with CInestil C41 and I'm having similar, could you link me to that thread please

Click to expand...

I did not. I made a stupid mistake once by developing in a half-empty oversized tank, which dropped my developer temperature by (unknown) but apparently large amount and undercooked my negs causing a cyan-ish cast after reversing. Otherwise, I was actually quite happy with this kit. Here's the thread and here's a random sample of a properly (following the instructions) developed roll in this kit:

RoboRepublic said:

I to loose 1-2 degrees, with in the first minute-.

Click to expand...

Isn't this the norm?

Вormental said:

@grat you just described the Cinestill C41 kit instructions, so you're not crazy at all.

Click to expand...

yeah, but I'm using the Unicolor kit.

I have thought about rolling my 4x5 drum in a sous vide bath at 104. But the unicolor instructions say fill the tank with water at 104 then drain then roll with developer at 104.

my neg scans seem ok.

Maybe unicolor compensated for the drop and figured it all out for us. Anyway, if you get consistent results, why not stick with it.