C-41 - Drift By or Temp Averaging

bvy · Nov 22, 2013

I'm curious if anyone is using "drift by" to maintain temperature in their C-41 film processing -- as opposed to using a water bath or some more elaborate set up (e.g. fish tank heater, slow cooker, etc.). Likewise, I'm curious if anyone is avoiding it for practical reasons. I'm looking for ways to simplify my C-41 processing. I'm NOT interested in tips on maintaining temperature, as I have that down already with a water bath -- but if it's not buying me anything that I can't easily fix when I print, then I'm willing to experiment with doing away with it altogether. (I don't mean to be belligerent, but I don't want the thread to evolve into yet another discussion on how to maintain temperature. I'm interested in this method specifically.)

I use a plastic Paterson tank with two tempered prewashes (at about 105F). If the developer goes in at 102F, after three-plus minutes it's dropped to about 98F. I believe PE calls this "temperature averaging," and he and others make reference to Kodak documentation on this (though I can't find the actual source). If that's not an outright endorsement, it's enough for me to consider it seriously. But I'd like to hear about some practical experiences first.

Thanks.

Lamar · Nov 22, 2013

I use two pots on the stove if I have only one spiral tank to process. It's easier and faster than breaking out the roaster. I heat one pot to 150-160F and use it to quickly preheat the chems to 102F or whatever. The second pot I heat to 103F. Since developer is the only thing the strict temperature is needed for, and then only for a bout 3.5 minutes, this works fine. Temps for bleach/fixer steps will easily stay in their wider temperature range. NOTE: The pots I'm using have a think stainless base that hold heat well. With thinner bottomed pots you may need to be a little more watchful of the temp.

Terry Christian · Nov 22, 2013

I use a hot water bath for C-41 as well, just hot water out of the tap, no heater or stovetop. I've found that if you're going to err on the side of a degree or two too warm or too cool, err on the side of too cool. Too warm gives me a slight bluish cast. (I'm using Kodak Flexicolor.)

Lamar · Nov 22, 2013

I just re-read your post and I think I missed your point the first time. You are actually wanting to avoid a water bath altogether, opting to start the developer time at temperature A and end at temperature B where (A + B) / 2 = developer temperature requirement. Is that correct? That equation would not be entirely accurate representation since the rate of temperature decrease won't be a linear function but I'm sure it's close enough given the deltas involved. I have not done this before but it is an intriguing proposition and seems entirely reasonable given development rates and rate of change of temperature are linear enough in the desired window for the given parameters. I guess if you really wanted to you could work out the correct equations and determine the rate of heat transfer coefficients for the materials involved then calculate your required starting temperature based on the ambient temperature in the room. Somehow you would have to figure in losses due to agitation, perhaps include that as part of the rate of heat transfer coefficient.

Gerald C Koch · Nov 22, 2013

Correct development requires good temperature control. I always use a water bath. No drift or averaging.

bvy · Nov 23, 2013

Thanks for the responses, Lamar, fully realize temperature decrease over time isn't linear, but as you say, it's "linear enough." Terry, that interesting because I've read things suggesting both to err on the too warm and too cool side. Gerald, I understand about correct development; I'm interested in experimenting in hearing from others who have done the same.

Terry Christian · Nov 23, 2013

bvy: The troubleshooting portion of the instruction sheet for the Rollei Digibase C-41 (liquid) kit also says that if the negatives appear more magenta than normal (i.e., the scans/prints more cyan) then the cause is developer that is too warm.

stefan4u · Nov 24, 2013

Some time ago, the German photo supplier „Phototechnik Kleinschmidt“ had a processing routine for their dilucolor c41, that will match your desires.

Heat up the soulutions to 40-42°C in a water bath.

Let the processing drum with the films preheat in that same water bath too.

Fill in developer if temperature is reached, immerse drum all 15 seconds.
Measure the developer temperature in the drum after 2 minutes and adopt final developing time, depending on measured temperature.

38° 03:15
37° 03:38
36° 04:04
35° 04:33
34° 05:06
33° 05:42
32° 06:23

Actually I don`t remember the exact times, I suppose values where rounded up/down to 5 seconds. I also have to say that I never tried this, but there where plenty of positive feedbacks in conjunction with this dilucolor chemistry a long time ago. But in the later editions of dilucolor this temperature drop method was not mentioned any more, so be warned that you will probably earn some unwanted side effects.

The given times are from a german photo forum.

http://aphog.com/forum/viewtopic.php?f=2&t=16988&p=168475&hilit=temperaturabfallmethode&sid=f9a408f9f2636ea31bcd708caea6a29d#p168475

Regards stefan

markbarendt · Nov 24, 2013

I started with drift by the made several upgrades on water bath and temp control.

Drift worked ok but the more accurate my temp control became the easier it got to print.

Gerald C Koch · Nov 25, 2013

markbarendt said:
the more accurate my temp control became the easier it got to print.

Exactly Why make work for yourself with negatives that are inconsistent and hard to print!

bvy · Nov 25, 2013

I did a "dry run" and noticed that with two prewashes at 105F, an ambient temperature of 70F, and NO tempering bath, that the temp only dropped two-and-a-half degrees. The water went in at 102F and came out at 99.5F. What I'll probably try next is a clip test just to satisfy my own curiosity. I'll shoot several frames of the same scene, and develop clips with and without the water bath.

I do make optical prints, and I do appreciate as little fuss as possible when it comes to filtering. What I might find is that drift is a better solution for people who only scan their negatives.

Lamar · Nov 25, 2013

That's less temperature drop than I anticipated. I thought with agitation you would be looking at an exit temp around 96F or so at best. I guess the 105F prewash helped that to some extent.

adelorenzo · Nov 25, 2013

I'm not sure what chemicals you are using but I use Tetenal kits and they provide alternative processing times for developing at 30 C (86 F) that might be something to try. It might be easier to maintain a lower temperature and the longer development times are said to help even out the process. Here's a pretty good write-up with comparisons:

http://paulagortazar.blogspot.ca/p/tetenal-c-41-rapid-negative-kit-review.html

RPC · Nov 25, 2013

Using a lower temperature is not the best way to solve the uneven development problems mentioned in the article. If it was due to agitation he should use a better method. Using a lower temperature always produces crossover. This has been discussed many times before in this forum.

Tom1956 · Nov 26, 2013

In 50 years in photography, every temperature I've ever used was a "drift-by". All temperatures are fleeting, with the best of processes and procedures. Depending on this "averaging " method as your process is not acceptable, imo. A color print starts to go warm toned when you get a degree high, and bluish a degree too low. Without an elaborate and pricey temp set-up, you must rely on cookpots, stoves, and refrigerators. But it does work, although it might take an hour of prep and dry-runs for a single print. But you have to get it right. 1/2 of a degree ±, is your "drift-by". And it's best to do your prep and dry-runs to where even that 1/2 doesn't show up on the thermometer.

adelorenzo · Nov 26, 2013

RPC said:
Using a lower temperature is not the best way to solve the uneven development problems mentioned in the article. If it was due to agitation he should use a better method. Using a lower temperature always produces crossover. This has been discussed many times before in this forum.

The lower temperature recipe is straight out of the instructions for the Tetenal C-41 kit. I don't think they would include it if it was guaranteed to get bad results.

RPC · Nov 26, 2013

adelorenzo said:
The lower temperature recipe is straight out of the instructions for the Tetenal C-41 kit. I don't think they would include it if it was guaranteed to get bad results.

The C-41 developer was designed to give parallel curves at 100 degrees F and nowhere else. If lower temperature developers could be used for C-41 and give said curves, then Kodak and Fuji would have done so, but they haven't. Other manufacturers in the past have made developers that used low temperatures, but if they had been successful they would likely still be around, but they're not. The results may look acceptable to you, but may not be to someone else. Users are urged to compare print results side by side between film developed at low temps and 100 degrees F (a gray scale or skin tones are preferable) before they decide to stick with a low temp process.

RPC · Nov 26, 2013

I would like to clarify the above post that when I said "100 degrees and nowhere else" I was not implying the drift through method should not be used. I was contrasting the standard 100 degree temp with lower temps such as 75, 85, etc. that some makers have used. I believe the drift through can work if you average the correct temperature.

bvy · Nov 26, 2013

Thanks. Like you, I wasn't interested in processing at cooler temperatures. My radius/target is still 100F.

It was this post by PE that got me to consider the idea seriously:
(there was a url link here which no longer exists)

Or. to quote:

I set the temp to about 102 and let it drop to about 98 over the 3'15" development time. It works just fine. Temperature averaging, as it is called, is mentioned on the EK web site.

chuck94022 · Nov 26, 2013

For what it's worth, I started with "drift by", but found that it made me so anxious that I had no enjoyment in the process. This is supposed to be a hobby for me, and hobbies are supposed to bring pleasure, not anxiety.

All anxiety vanished when I invested in constructing an accurate water bath capable of holding all chemicals at the correct temperature, plus/minus one tenth of a degree, for as long as I desire.

One thing in particular that is problematic for drift by is if you have to make multiple runs. There is a delay between runs getting the temperature back up to snuff, which I found annoying.

I also find color correction due to poorly developed negatives to be a royal pain, regardless of whether you are optically printing or scanning. I'd rather get the negatives right at the beginning, it saves a lot of headache.

Of course, if you are doing c-41 based black and white, I guess none of this is a problem!

Edit: re-reading the thread, I should note that my "drift by" was in a water bath. It was the bath that was "drifting by", so I was typically well within specs for normal temperature. It just always added stress to keep the bath at temp by hand.

adelorenzo · Nov 26, 2013

RPC said:
The C-41 developer was designed to give parallel curves at 100 degrees F and nowhere else. If lower temperature developers could be used for C-41 and give said curves, then Kodak and Fuji would have done so, but they haven't. Other manufacturers in the past have made developers that used low temperatures, but if they had been successful they would likely still be around, but they're not. The results may look acceptable to you, but may not be to someone else. Users are urged to compare print results side by side between film developed at low temps and 100 degrees F (a gray scale or skin tones are preferable) before they decide to stick with a low temp process.

I've never tried it as I use a Jobo for C-41 at 38 degrees so I can't comment on the results. Since the OP was looking for ideas on processing without temperature control I figured I would throw that one out there for consideration, is all.

C-41 - Drift By or Temp Averaging

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