Room temperature C41

bobmercier · Jul 11, 2011

I've been processing color film at home with some success. I'd modified an aquarium heater and could consistently get 100deg but it was a pain in the ass and took alot of time. I've recently been working with the Rolli kit from freestyle, it has separate bleach/fix so it has an additional step over the Unicolor kit, adding to the time. Interestingly the directions indicate it can be used at less than 100deg so I decided to see how it'd do at room temperature. The first three images are Kodak Portra 160 (4x5) at 68f for 16min, 18min and 20min. I'd planned 22min as well but blew the development on that one. The last image is from a roll of Fujicolor Pro 400, 120 film, developed at 68f for 21min, 20sec agitation initially then 4 inversions every minute; bleach for 7min then fix for 8, same agitation routine. Also, rinse with water before and between each step, mostly to reduce contamination of the chemicals.

It looks promising. I've ordered a couple more Unicolor kits to see if it will work as well. I also want to try it with Ektacolor 100.

p.s. I see the attachments were re-ordered somewhat. img358 is 16min, img359 is 18min and img360 is 20min. Thanks.

georgegrosu · Jul 11, 2011

bobmercier, depends what level of results you are intended to get.
The instruction manual for use of Rollei/Compard C-41 Color Film Processing Kit - PROCESSING is written:

This general information is based on intensive tests and experiences of many users of the DIGIBASE C-41 chemistry, who have reported their results and have given allowance for publishing. No responsibility is accepted for the correctness of this information.

http://www.freestylephoto.biz/pdf/product_pdfs/compard/Compard_C41_Instructions.pdf
If you want to test, you should use a gray scale - at least.
It gives you information about the contrast, color balance, ....
Developed a test and a laboratory.
George

spacer · Jul 11, 2011

Well, the images came out pretty sharp. The color ain't perfect, but at least the universe didn't implode when you soaked 'em at 68F. That's a good sign.

Then again, maybe Mario is a bit faded in real life...

Athiril · Jul 11, 2011

Want consistent temp for normal C-41? Use a plastic tank, pre-soak with ~45c water, agitate, it'll drop down a bit, tank and film will be around right temp, heat up dev to right temp, process away for 3m 15s.

dMax-dMin suffers I've found at low temp.

Rudeofus · Jul 11, 2011

While I would love room temperature processing, I am afraid that room temperature varies way too much for repeatable results. In winter it easily falls to 20°C (why waste a fortune on room heating?), while in summer 30°C or more are not rare, even at night. With a bucket of hot water I think it's a lot easier to get 38°C right than anything between 20° and 30°C.

georgegrosu · Jul 11, 2011

I see this test as a way to reduce negative image contrast in color. The difference in contrast between the developed image from 16 min to the 18 min is notable. You should see the loss of sensitivity of the film, possibly to correct the shooting.
I think it is better to test the 2-3 types of films. Not all films respond equally to such processing.
In the processing to 37.8 ° C the color negatives should not be something that scares you. Work with a plastic tank and a sink for thermostat.
I put developer in a plastic tank, make the temperature and put the film from the black bag . In three minutes and something the developer temperature will vary not more than 0.1 - 0.2 ° C.
Better not do Pre-Soaking.
Intermediate washings are beneficial.
George

Lee L · Jul 11, 2011

Rather than judging the comparison from the posted images immediately, my first reaction is to ask if the scans were identical, with the scanning settings for color balance and contrast locked in, on which image they were locked, and also to ask how the OP's system is color calibrated, if at all. It would be nice to know about the scanning method and consistency there before attributing all the variations to the developing. I know we're not supposed to discuss scanning per se, but in this case it's critically important to judging the results of a test.

Lee

P.S. Looks like it was an Epson flatbed scanner, as the images have an Epson standard RGB profile with gamma 1.8, which might explain some of the reduced contrast noted by George.

epatsellis · Jul 11, 2011

I'd love to see this done with control strips and densitometer measurements. On page 5-29 of Z-131, there's a chart showing the effect of low temperature on the various densities. at -4F from aim, there is a significant decrease in Dmax and Hd-Ld:

Note that the densities decreases differently, based on layer order and the diffusion rate through each. While I imagine one could correct for some of the color balance change, there comes a point where I think you're approaching SOL.

Lee L · Jul 11, 2011

epatsellis said:
Note that the densities decrease differently, based on layer order and the diffusion rate through each. While I imagine one could correct for some of the color balance change, there comes a point where I think you're approaching SOL.

In other words, color crossover, which is correctable in software (and which an automatic scan with color correction will mask to varying degrees), but which is difficult or impossible to overcome when printing the neg directly to enlarging paper with conventional analog methods. You can't dial one one color correction into the shadows and a different color correction into the highlights with an analog enlarger.

Lee

georgegrosu · Jul 11, 2011

epatsellis -

I'd love to see this done with control strips and densitometer measurements.

And I would like to see curves sensitometrice.
PROCESS MONITORING AND TROUBLESHOOTING (Manuals: Z-131) is designed as a guide for color negative process – photo.
For color negative film process - cinematography there is a similar material which is called Processing KODAK Motion Picture Films, Module 8. Effects of Mechanical & Chemical Variations in Process ECN-2.
http://motion.kodak.com/motion/uploadedFiles/h24_08.pdf Figure 8-1 Effects of Time Variations—5213, 5254, and 5242 Films in Process ECN-2 Developer and Figure 8-2 Effects of Temperature Variations—5213, 5254, and 5242 Films in Process ECN-2 Developer
This variation of time and temperature are identical, but are presented the types of color negative films (for ECN 2). Variations of density, variations obtained for the same variation time (± 40 sec) and the same variation in temperature (± 4 ° F) in the ECN 2 (process color negative film for cinematografy)) are higher.
It must be said that this information is quite indicative that the process of bobmercier time it has about 7 times greater than the variation shown in 131_05 Z and the temperature is below about 7 times the variation shown in Z 131_05. In my opinion, 131_05 Z data can not be extrapolated so far.
After me, so high variations of time and temperature may occur color balance change for film.
George

RPC · Jul 11, 2011

This has been discussed before here on APUG by PE and others, and low temps with C-41 always result in crossover. It may be acceptable to some but likely not to most. Even if it can be fixed in software, wouldn't it be easier just to develop at the correct temperature, and have good negatives?

RPC

Photo Engineer · Jul 11, 2011

epatsellis said:
I'd love to see this done with control strips and densitometer measurements. On page 5-29 of Z-131, there's a chart showing the effect of low temperature on the various densities. at -4F from aim, there is a significant decrease in Dmax and Hd-Ld:

Note that the densities decreases differently, based on layer order and the diffusion rate through each. While I imagine one could correct for some of the color balance change, there comes a point where I think you're approaching SOL.

This mirrors what I have seen in my own darkroom and in experiments at EK. Nevertheless, the OP has shown some of the best results at 68F that I have ever seen, so there is some promise here. IDK how good this will be in the long run. As stated earlier, some gray scales are needed along with color patches and also a comparison with a "correct" process.

PE

epatsellis · Jul 11, 2011

I've been down that road several years ago, with scanning, you might be able to get away with it, but if you look at the control strips, they're so cattywumpus that you wonder how the heck you ever were able to get something to even resemble white. What concerns me most is that we don't know what the original scene looked like, colors, etc. Now doing this with a Macbeth color checker would at least be a step in the right direction. But to dogmatically accept that the only thing that changes is density and saturation is just a little too far for me.

In the words of the late Ronald Reagan, "Trust, but verify". Show me some standardized color patches, heck even a Q13 or Q14 gray scale would work wonders for illustrating color crossovers, btw. I realize not everyone has a densitometer and a box of control strips hanging around, so one of these alternatives would work nearly as well.

mabman · Jul 11, 2011

Because I do room temp. semi-stand with B&W, I tried similar reduced-agitation with C-41 at room temp a while back (not quite "semi-stand" exactly because I used the dev at full-strength). I have yet to scan or print anything (the purpose was to see if it worked at all), and I'm not using a "standard" C-41 kit (a local group was able to divide the chemical tablets contained in a decommissioned Konica processor's kit for hand tank use), but to my eye the negs look "normal" when using a fresh roll of film. As I recall I did 5 taurus inversions, left it for about 10 min, did another 5 inversions, and then left it for about 11 minutes. I then did bleach and fix steps also at room temp - I seem to recall I increased the time a bit for each step. Sorry for the imprecision, I don't have my notes in front of me right now.

Anyway, if people are interested I can dig out the negatives and scan them in the next few days. It's an interesting experiment - I was pleasantly surprised to see that C-41 could work in those conditions at all.

GeorgK · Jul 12, 2011

Don't want to get personal, but it looks like some people never run out of ideas how to ruin tons of film for usless results.
Shooting film for quality reasons, but not willing to invest a few minutes to heat the developer does not make sense. Off-temperature C41 will always have questionable results, and even if it seems to somehow work one time, it will give unpredictable results the next time with a different motif, film, or developer. OTOH, a lot of "die-hard analog aficionados" accept unbelievable low standards for the results of their "labour of love".
Everybody is free to waste his own time and money, but I guess a beginner will get a completely wrong picture of lab work from looking at all these "alternative processing" treads at APUG.

Georg

georgegrosu · Jul 12, 2011

Georg, you have never tried something else than the recommended solutions?
Perhaps some people go through such experience.
Once you have learned something about film processing can try other options you see opportunities for you. Perhaps we are not able to understand why they try other ways of working. Or maybe they are not sufficiently understand the motivations for them tests.
And me personally I do not feel justified procesing of C-41 at 20 °C.
It is important to you to learn something of these tests.
Requirements on the test results are different depending on the person.
George

RPC · Jul 12, 2011

Nothing wrong with experimentation, let's not discourage it.

Based on what I have experienced myself, and what I have read here on APUG and other literature, I think it is unlikely that conventional C-41 chemistry can ever be made to give generally acceptable results at low temperatures, but that doesn't mean I would discourage anyone from trying. But I think a better solution would be to experiment with altered chemistry. Perhaps someone with chemical know-how and ambition could produce chemistry that gives good results at low temperatures with modern films. Unfortunately, there does not seem to be a lot of interest in color chemistry experimentation.

RPC

pentaxuser · Jul 12, 2011

Go back far enough in time to maybe the 70s or 60s and as I recall things the equivalent of C41 processing was done at much lower temps.

So was lower temp developing always a second best solution or was it simply that an improved process called C41 demanded 100F?

Even if you could buy stuff for the older low temp process today would the negs eventually suffer compared modern C41 negs processed at 100F?

Sounds as if we might need PE to chime in here as he must be one of the few with enough experience and grey hairs to comment on it meaningfully

pentaxuser

RPC · Jul 13, 2011

I don't know if a high or low temperature process matters per se as as far as quality goes, but I would guess the high temp we use for C-41 was chosen to help labs process faster as color became more popular, not because of any better quality. My gut feeling is that a lower temp process would always be easier to design, and have more headroom and thus less chance for error but by the same token would probably always take longer to process.

RPC

wblynch · Jul 13, 2011

Maybe the higher temperature opens the color layers to let the chemistry in?

I have seen where people use cold C-41 to get fair color from ancient C-22 film.

But even out on the prairie, with a wagon train, one should be able to rustle up some hot water to get those C-41 chems up to 102*f. Cook those negatives alongside a pot of beans.

georgegrosu · Jul 13, 2011

Color negatives produced for the C-41proces will surely give the best photographic results at the temperature recommended. Working at half the recommended temperature, even with time compensation I think it will generate a bad color balans. Sensitometrice curves cross. See that on a gray scale. Using a 18% gray than you may be wrong. The gri can be corrected, but what happens with lighter or darker grays do not see. I use for photo color negatives - ECN 2 process. ECN 2 is for motion picture film. I use it for about 25 years. It is at hand and know well.
George

Photo Engineer · Jul 13, 2011

C41 films from Kodak and Fuji rely on the use of DIR couplers. These couplers release chemicals that inhibit development around the development site and also diffuse to adjacent layers (along with released Iodide) to correct color rendition by inhibition. All of this chemistry including release and diffusion, is adjusted to work best at 100F in the authentic C41 developer. Therefore, you can degrade color, sharpness and grain by using the wrong process.

It may not happen. I have thought of several chemistry combinations to compensate for a low temperature, but testing this is hard and expensive if it is to be done right.

So, this is quite esoteric chemistry that you are tampering with. I am just surprised to see it work out so well. But, we have no comparisons, nor do we have data on grain and sharpness.

PE

railwayman3 · Jul 19, 2011

An old-time lab technician told me, some years ago, that the change of processing to 100F was much appreciated at the time C-41 was introduced , as this is always above normal room temperature. So all that was needed was a thermostatically controlled heating of the tanks, whereas before a solution temperature of 68F could need both heating and cooling in variable climates. Never seen any other specific references to this, but it seems logical?

hjesus · Aug 28, 2015

Yes, I am a little late, but...
IMMO, if you can manage to develop without temperature control and get acceptable results, adjustable at scanner or software, why not? It is much easier! Of course, if you are working for others or if you want to get perfection, follow the manufacturers recommendation.

Rudeofus · Aug 28, 2015

hjesus said:
IMMO, if you can manage to develop without temperature control and get acceptable results, adjustable at scanner or software, why not? It is much easier! Of course, if you are working for others or if you want to get perfection, follow the manufacturers recommendation.

The problem is that you need all three layers fully developed (i.e. not underdeveloped) in order to reach full film speed. If you overdevelop the top layers by the time you fully developed the bottom most layer, you have excessive grain in that layer, same as you get when pushing in B&W. Processing according to spec (i.e. 38°C/100°F) guarantees that all thee color layers are fully developed at the same time.

All that may not be visible in web sized images produced by cheesy flat bed scanners, but it's not something you can fix in a digital work flow if you ever want a high resolution print from one of these negs.

Room temperature C41

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