Constant developing temperatures

<p>I plan to start doing my own c-41. From what I read the tolerances on developer are very tight. I will be using a large plastic tub full of water as a temperature reservoir. Will this be sufficient to achieve required temperature and maintain or will that vary to much during the process or will I need to add energy during the process. If so, 3 possibilities come come to mind. 1- place a heating pad under the tub. 2- Use a hair dryer blowing against the exterior wall at an angle/distance to be determined. 3- Use a fish tank heater.<br>

Do any of these sound practicle?</p>

<p> </p>

<p>I use the same plastic bowl that I wash my plates in (dinner plates, not 4x5-inch ones!). Depending on the season, I sometimes need to maintain the temperature of the water during a session. I have a fish-tank heater, and have used it with some success; mine is only 75W though, and I think a more powerful unit would be better. I often just keep an eye on the temperature, and have a kettle of hot water handy.<br /> <br /> I think hot air would be a poor method, because the heat capacity of air is so low relative to the water you're trying to keep warm. The noise of a hair dryer would drive me crazy, too.</p>

<p>This question has been discussed in the Flickr 'Do It Yourself Color' group, and you can read other people's solutions there (e.g. in <a href="https://www.flickr.com/groups/diy_color/discuss/72157652462230395/">this thread</a> about how critical temperature is/isn't).</p>

<p>I used to develop E-6 (which, if memory serves, is even more sensitive to temperature than C-41) using a large tub. I poured each of the chemicals needed into bottles which I put in the tub. I then filled the tub with hot water until the water reached the high side of the allowable temperature and followed the directions. <br>

As long as you are careful in observing the proper times and temperatures for each phase of the process you will be okay.<br>

<br />Jerry</p>

 

<p>Only you can answer your question, here's how to do it.<br>

Fill the tank with reels with water at the required temperature. Let it sit 5 minutes then pour the water out and refill with water the same temperature as the required developing temperature, insert the thermometer in the tank and place it in the tempering bath. Check the temperature at the end of the required developing time. Continue monitoring the temperature for the total time of the other processing steps plus the drain and fill times.<br>

The temperature change should be ±.5°F for the developer and ±3°F for the other steps. The closer the temperatures remain to each other the better the results.<br>

The size of the tempering bath, the temperature of the environment and the work surface will determine the temperature of the tempering bath.<br>

Several years ago I processed some E100G. The room was 58°F, the ceramic counter top was cold to the touch. I used a two pan tempering bath. Each pan held approximately 2 gallons water. The bottom pan was 110°F, the top pan was 105°F, and the processing temperature of 103°F shifted less than .5°F during the entire processing session. I got some excellent 4x5 chromes that day.</p>

 

<p>I've used a similar system to what Charles used and it works fine. If you do exceed the recommended temperature change or if your thermometer is off a bit, you can usually correct color shifts or density after you scan.</p>

<p>You guys are making me feel pretty lazy for buying a used Jobo CPE2! Honestly though, the popularity of "sous vide" cooking has led to a huge market for cheap water bath temp controllers. You can get a nice new digitally controlled termpering bath circulator for $150-$170 online. Other than that, after using the Jobo for a year, I've realized the two most important (and not expensive) items are a good thermometer and 5-6 500ml sized screw top plastic containers. I've been re-using plastic 500ml milk containers, they're a nice size for 1-2 rolls in a tank.</p>

I take from what everyone says it is a

matter of getting the routine down pat

and developing an intuitive sense and

that only comes with experience and

probably some frustrating disasters.

The reason I brought up the fish tank

heater was that even though it would

not maintain the temperature it would

slow down the rate of heat loss to give

me a little more time to get routinized.

<p>If you can't keep the temperature from varying too much, you can keep the average right.</p>

<p>If it starts 2 degrees higher, and ends 2 degrees lower, on average it is close enough. This is more usual done for prints, but should work for film, too. </p>

<p>Some years ago, I used to do E6 with a tray full of warm water, and a bowl of hotter water. I could pour a little hot water in to keep it warm enough. </p>

<p>For my C-41 and E-6 developing I have a styrofoam box that was used to ship frozen steaks in. They place the frozen steaks in this box with dry ice and they stay frozen until they reach their destination. This box has a lid and sides that are about 2" thick and its interior is big enough to hold about a 12-pack of beer -- just to give you an idea of the size. Anyway, I find it works quite well for maintaining temperatures during the development process. I fill it with hot water, add the bottles of developer with at least one bottle's cap unscrewed so I can insert a thermometer, and then wait for the system to come to equilibrium. Then I adjust as necessary using either cold water or hot water. I do this with an 8-ounce cup, where I'll bail out a portion and then add an equivalent portion of hot or cold water until I get the temp where I want it.</p>

<p>If you don't have access to one of these boxes, you can buy a cheapo styrofoam cooler for beer/soft drinks at your local grocery and use it instead. These styro coolers' walls are thinner, but they're thick enough to act as good insulators.</p>

<p>Occasionally when I'm developing, I'll see the temps begin to fall, so I'll bail and add hot water during the development process. It helps if you're able to do two things at once (agitation and baiing in this case).</p>

 

<p>"I use the same plastic bowl that I wash my plates in (dinner plates, not 4x5-inch ones!)."<br /><br />I don't know about the rest of you, but I'm going to remember that the next time Pete invites us all over for dinner. :)<br /><br />I have a stainless steel "Road Warrior" tank. It holds four 32-ounce developing tanks in a row, surrounded in water up to within about a quarter inch of their tops. It has a slot in the bottom where I put a submergible Dev-Tech heater. (Not sure, but the tank might have been made by Dev Tech). The heater has a thermostat so it cuts on and off as needed. This rig came from UPI, where I used to be a reporter and was friends with the photographers.<br /><br />I use the Jobo C-41 Press Kit. The chemicals get mixed from powder and once mixed I store the developer, blix and stabilizer in three of the tanks. The fourth tank is for the film being developed, and it holds four rolls of 35 or two of 120.<br /><br />The Press Kit instructions recommend 102F for hand processing. So I get tap water to about 100F and fill up the Road Warrior maybe an hour before I'm going to develop. (probably doesn't need to be that long) I turn on the heater, and I've already got the thermostat dialed in so that it keeps the chemicals in the tanks at 102F. (Not sure if the water is the same, but I measure the temp from the developer.)<br /><br />By the time I'm ready to develop the chemicals are at the proper temperature. I pour the developer into the tank with the film into it, pour it back, then the blix, etc. I supposed I could lift the reels from one tank to the next but I'd have to do that in the dark so I find it more convenient to pour it in and out. Between the water bath and the thermostat on the heater, the temperature is constant from start to finish and from one batch of film to the next.<br /><br />My B&W chemicals are used one shot and go down the drain, but for C-41 I reuse the chemicals until I hit the rated capacity of 12 24-exposure rolls or until they're a month old, whichever comes first, as recommended by Jobo. (I rarely shoot film anymore, so usually the month is up before I've had a dozen rolls to run through. But at $20 or so I figure I break even compared to going to the lab on four rolls and any rolls beyond that are free.)<br /><br />This is the way color was developed at UPI when I was there in the 80s, both in the bureau and on the road. There are many ways to accomplish the same thing but this works well for me.</p>

I did my first roll last night and used a fairly decent picnic cooler for my water bath. Left the water in it last night and the

temp was 103*F and closed the cover when done at 9:50 PM. The temperature this morning was 96*F this morning at

7:50 AM. Using a good cooler certainly certainly allayed any anxiety about maintaining proper temperature. Too bad that

in my first attempt for some silly reason I opened the wrong part of the tank and exposed the film and that kind of

disrupted all my well laid out choreography,

<p>Go buy a thermostatic waterbath somewhere. It is the only permanent solution.</p>

<p>Of course that should be the end discussion but there are some people (person) who will not accept my justification to buy one coupled with my limited resources and space. At the same time I see people who do with less. I tested the performance of a decent ice chest and found very good temperature stability over a long period. Just processed my first roll ever without rechecking temp till done. Temp dropped 2.5*F over 2 hours and results were decent for a first try. Not trying to be facetious of course having a regulated system is the real answer.</p><div></div>

<p>Donald, I think your solution is a perfectly good one. I'm the one who uses a styrofoam container used to ship steaks in. It maintains temps very well. Any loss of temperature is due to the top being open to ambient temps, otherwise its thermal properties would probably be just as good as your cooler's.<br>

Being a person of limited means, I typically tune out expensive solutions to problems I'm facing because there's no way I can afford them, so I figure out other ways to get things done. Hey, the important thing in this case is maintaining temp, and if it can be done cheaply, then the results will be identical, all other things being equal.</p>

 

Michael, I think it was you who mentioned that before and gave me the idea. Right after I read your post ( I think it was

you or then something similar) I was walking through my garage and there was the cooler. So I just put it in the tub and fill

it from the tap and can drain down the drain. I closed the top when finished one time and forgot about it until morning and

when I opened it the next day it was still close to original temp. The nice thing about this cooler is it has wheels and

telescoping handle like on luggage. I stow all my chemicals and all necessary equipment in it and wheel it out of there

way like a mini portable developing operation.