Colour Comparison: C-41 at different temperatures

[pentaxuser]

RA-4 can be developed at room temperature using Kodak Ektacolor RA/RT chemicals, as detailed in posts by the late Ron Mowrey here on photrio.

numerous threads on the topic of RA-4 at room temperature. Here is one: https://www.photrio.com/forum/threads/hot-plates-for-water-bath.60626/

Good luck finding the chems with the current supply chain situation, though.

I think that there is general agreement that RA4 can be successfully developed at 20C so do we know that in colour paper the dyes' difference do account for lack of crossover that the dyes in film cannot? I'd presume that as it was PE who stated that RA4 was fine at 20C but colour crossover was likely/ inevitable at less than 37.77C then he may have said why the RA4 process worked OK at 20C but C41 did not at less than 37.77 C ( Let's call it 38C for convenience)

So does anyone know if he gave reasons?

pentaxuser

 

[Nodda Duma]

It was the specifics of the particular RT chemistry. I remember reading the thread where he explained, but don’t recall the details.

Having made numerous RA-4 prints at room temp per his recommendations, I can say color crossover was never evident.

 

[Donald Qualls]

RA-4 can be developed at room temperature using Kodak Ektacolor RA/RT chemicals, as detailed in posts by the late Ron Mowrey here on photrio.

<snip> Good luck finding the chems with the current supply chain situation, though.

I meant that it would take printing (attempting to print) RA-4 from my "drift through" temperature control negatives to be sure they don't have crossovers; they look good to me in scans, but I don't have the eye to easily see crossover.

As it happens, I do have a full set of Ektacolor RA chemicals that I purchased a year or so ago and haven't opened, and am well aware that others have successfully processed RA-4 in this chemistry at room temp (just requires longer bath times). Still getting my enlarger fully up to par.

 

[Nodda Duma]

I hear ya. The darkroom at my shop is *I think* gtg for color, and I bought some 16x20 Fuji Crystal Archive that I’m itching to print. Hoping to find some time to play over the holiday break.

 

[Donald Qualls]

Photographically, my holiday will be finishing an in-progress modification to an RB67 roll holder (24x70 frame mask on 220 back), mixing EcoPro and Flexicolor developer/replenishers, hopefully catching up my backlogged film (got 8-9 rolls that need developing) -- and installing a new video card and RAM upgrade in my desktop computer. If the roll back mod goes right, I also hope to get out to shoot some pano with my 50 mm + 0.46x wide angle adapter (=> 23 mm focal length, 120+ degrees wide).

 

[Adrian Bacon]

I know this thread is all about experimentation, and there’s nothing wrong with that, but it’s not that difficult to get the process to run at about 100 degrees. The closer and more accurate you can make it, the better, but if you’re off a bit but at least in the ball park, it generally results in better looking negatives than if you’re way off.

@drmoss_ca if this is largely being driven by trying to save time, I’ve found that sometimes simple things like order of operations makes all the difference in the world. Not saying you haven’t figured this out or couldn’t think of that, but you’d be amazed how often somebody points something out to somebody and they respond with “I didn’t think of that”.

that said, start heating your chems when you mix them, and do that part first. That way they can be coming up to temp while you’re doing everything else. An investment a plastic tub large enough to hold all your bottles and a sous vide cooker makes life 100 times easier. Just fill the tub, set the desired temp on the cooker, turn it on and star mixing up your chems and put the bottles in the water bath, then go prep your film for processing. Unless you’ve got some wonky bottles, they should be up to temp in 15-20 minutes, by then you should have your film in the tank and be preheating the tank. The actual process with the standard c-41 chems is less than 30 minutes to get to the final wash. I’ve found that it’s pretty simple and straightforward to run a batch from start to finish in about an hour. You can cut that down quite a lot by getting into the rapid access chemicals, which dramatically cuts your bleach and fix times down.

if 15-20 minutes to get up to temp is too long for you, then you can also start by filling the tub with the hottest water you can get from the tap and put the bottles in that with the cooker set at the desired temp then let it settle down to the desired temp, though, in my experience that doesn’t really shorten the time much, and I find that it takes me about 10-15 minutes to twincheck my film and get a batch loaded in a tank, and another ~5 minutes to start pre-heating the tank so my temperature drop going into the tank isn’t too large, and the two kind of converge so that the chems are at temp and my tank is ready to go at about the same time.

sure some of this means you gotta spend some money, but how much is your time worth? Spending a little cash to get a process that very consistently and reliably runs pretty correctly in about an hour saves how much more time elsewhere, like when scanning?

 

[koraks]

I think that there is general agreement that RA4 can be successfully developed at 20C so do we know that in colour paper the dyes' difference do account for lack of crossover that the dyes in film cannot?

RA4 develops to completion, C41 doesn't. I think that difference is very relevant here.

 

[drmoss_ca]

@drmoss_ca if this is largely being driven by trying to save time, I’ve found that sometimes simple things like order of operations makes all the difference in the world. Not saying you haven’t figured this out or couldn’t think of that, but you’d be amazed how often somebody points something out to somebody and they respond with “I didn’t think of that”.

Yes, time saving is my issue. I don't really want to buy more stuff right now, as I'm attempting not to die of leukemia and managing a move to a smaller house for my widow-to-be at the same time. As I have explained above, a washing-up bowl of hot water takes around an hour and a bit to get solutions in plastic graduates to 102º (recommended by powder presskits) and a couple of refreshments of hot water along the way. I'll try the careful microwaving first. If I experience some miracle or two, I may go the sous-vide route in the future.

Here's another pair of photos that are not [The Scottish play] colour charts. You can likely guess by now which is room temp and which is 39º/102º:





Even without objective colour charts, it's pretty obvious that there is a consistent purple cast to the room temperature process, which is to be expected according to PE. I guess all I am saying in this thread is 'don't do this unless you want funny colours'.

 

[pentaxuser]

RA4 develops to completion, C41 doesn't. I think that difference is very relevant here.

Thanks and good point.

pentaxuser

 

[MattKing]

RA4 develops to completion, C41 doesn't. I think that difference is very relevant here.

And of course, RA4 paper is considerably less sensitive ("slower") than C41 film.
As a matter of curiosity only, I wonder what the crossover behavior of very slow films (e.g. internegative film) would have been if off temperature development was used.

 

[Anon Ymous]

Ron posted several comments here stating that every layer in C-41 emulsion is optimized for 100F. Maybe I will find a day to kill and develop 3 identically exposed rolls at 95F, 100F, and 105F to see how much of a problem can result from moderate temperature deviations.

3 rolls would be an overkill, just setup a colour chart and shoot enough frames to develop at the temperatures you're interested in. While you are at it, you may also try at "room temperature" or thereabouts.

 

[Adrian Bacon]

Ron posted several comments here stating that every layer in C-41 emulsion is optimized for 100F. Maybe I will find a day to kill and develop 3 identically exposed rolls at 95F, 100F, and 105F to see how much of a problem can result from moderate temperature deviations.

They're optimized for 100F so that printing onto RA-4 paper works as well as it does. Lower and higher temperatures just results in different gammas for each color layer (which shows up as color crossover when printing on RA-4). If digitizing, it's less of an issue as long as you know what the gamma for each color channel is, it's easy enough to linearize back out and have correct colors after white balancing. All that said, it's still best to be as close to 100F as you can reasonably get.

 

[Nodda Duma]

RA4 develops to completion, C41 doesn't. I think that difference is very relevant here.

I agree with pentaxuser.. very valid point and thanks for making it.

 

[Adrian Bacon]

Yes, time saving is my issue. I don't really want to buy more stuff right now, as I'm attempting not to die of leukemia and managing a move to a smaller house for my widow-to-be at the same time. As I have explained above, a washing-up bowl of hot water takes around an hour and a bit to get solutions in plastic graduates to 102º (recommended by powder presskits) and a couple of refreshments of hot water along the way. I'll try the careful microwaving first. If I experience some miracle or two, I may go the sous-vide route in the future.

Hot water from the tap? That's a long time. You're losing a huge amount of heat out of the bowl, even with refreshes. If you don't want to spend any money, it might be worth it to go with a higher bowl temperature by putting a fair amount of the water in the microwave and getting it up to a pretty good temperature (80-90C) if you can't fit your graduates in the microwave. I'd maybe get a good half of the water getting up to a really high temperature in the microwave and pre-heat the bowl by filling it with the tap on full hot, at the same time, then when the microwave water is up to temperature, pour half of the water out of the bowl, put the graduates in, then top if off with the microwave water. Your biggest issue is going to be heat loss, so it's better to overshoot the heat in the graduate, then monitor it and go when it settles to the temperature you want instead of trying to get it up to that temperature and go when you get it there. The higher you can get your starting temperature in the bath without burning yourself the better. Also, since heat loss is the enemy, it might be worth it to try wrapping the bowl in a towel to act a little like an insulator.

Also, if you have a glass graduate, it might just be simpler to go with two baths. One larger one for the everything except the developer and use the normal plastic graduates for that (since those aren't nearly as temperature sensitive), then have a smaller bath with the glass graduate and maybe have the full hot trickling into that to get it up to temperature faster. All that being said, if you decide to go with the cooker route, if you know you're going to be developing that day, it's even pretty simple to just set it up first thing in the morning then do your developing when you get to it. The cookers are designed to maintain a given temperature for hours on end, so you don't really have to set it up right before you're going to develop, you can set it up way earlier and let it just do its thing while you go have a life.

 

[Anon Ymous]

I use borosilicate glass beakers. I can use a small camping stove burner to get my chemicals to the desired temperature in very short time. As @Adrian Bacon pointed out, it's better to overshoot slightly and monitor temperature. These glass beakers are the lab type and they're quite cheap actually.

 

[btaylor]

A cheap styrofoam cooler makes an excellent container for your water bath, heat loss is obviously minimized. The “drift by” method is easy- over heat the water bath, put the lid on and then check the temp of your materials once in awhile until you hit your target, then process. It’s not complicated. At $16 I have also found this to be useful: https://www.amazon.com/1000W-110V-P...t=&hvlocphy=9030966&hvtargid=pla-869408429900

 

[Donald Qualls]

At $16 I have also found this to be useful: https://www.amazon.com/1000W-110V-P...t=&hvlocphy=9030966&hvtargid=pla-869408429900

For just about twice that money, you can get a sous vide with 1 degree or better temperature control over a far wider range than you need, circulation, and a shutoff timer. Still only about what three rolls of big brand 120 would cost.

 

[btaylor]

For just about twice that money, you can get a sous vide with 1 degree or better temperature control over a far wider range than you need, circulation, and a shutoff timer. Still only about what three rolls of big brand 120 would cost.

I am sure the sous vide units are terrific, cheapest I found on Amazon was about $50. At the time I bought the bucket heater they started at $120. Frankly, the bucket heater works well enough that I haven’t bothered with the sous vide, just have to pay a little more attention.

 

[Donald Qualls]

I paid under $35 plus very reasonable (from US) shipping for mine via eBay. I like the ability to fill the tub with water that's a little under temp, drop the bottles in, and go do something else, then come back when it's convenient.

 

[Donald Qualls]

Basically, a sous vide only helps eliminating the last step (waiting for the temperature to drop), and also makes it easier to develop multiple tanks.

Both true. I did it your way the first time I had a color processing setup, worked fine. I can process more or less all day with the sous vide (unplug for a few minutes while I load the next tank of film, if I didn't have enough tank capacity to load it all at once). I've seen photos of bags over the control head of a sous vide, too, so you can leave it on and still have a darkroom.

 

[drmoss_ca]

Your microwave will differ from mine, which is 30+ years old. In mine, 70 seconds will make 300ml of solution get to 39ºC/100ºF. A splendid bit of knowledge, until I remembered when dealing with the resulting leak, that a Rondinax requires 200ml of solution rather than 300ml....

Say after me: Rondinax 60 needs 150ml, Rondinax 35 needs 200ml and the blasted Lab-Box needs 300ml whatever the film format it is about to ruin.