C41 Color Processing for Dummies

[nickandre]

tiberiustibz submitted a new resource:

(there was a url link here which no longer exists) - C41 Color Processing for Dummies

By Nicholas Andre

It's unfortunate that the art of color processing/printing is disregarded. Whatever the reason, people insist that it is "toxic" and difficult. This is not true! I find it to be a quite enjoyable experience. Those who will appreciate it the most are those who have worked with Black and White printing for a while.

Before you start color work, it would be best if you had some experience with Black and White work first especially for rolling film and printing. The...

(there was a url link here which no longer exists)

 

[Ian Grant]

Should the film be boiled, water boils at 100 degrees, unfortunately you've not specified °C or °F !!!!

The International standard for measuring temperatures is degrees Celsius (Centigrade).

 

[nickandre]

Preparation:

As such the chemistry for color work is almost all found in a black and white darkroom. Unlike B&W work, however, the color process requires careful control to develop each layer correctly. Development at the incorrect temperature results in nasty problems. Optimal temperature is 1/4 of a degree either side of 100 degrees F.

I specified. Is there no way to edit though? It would help...

 

[fotch]

I specified. Is there no way to edit though? It would help...

Your original post was not a problem for me, but then again, I am not an Internationalist.

 

[Peter de Groot]

Just a dummy question. Is temperature the most critical when developping? Meaning with developing you have to keep it withen the 1/4 degree variation? And with the following steps it is not soo critical?

 

[bobwysiwyg]

Tiber,

Nice write-up. I hope to try color some time, so hope you don't mind, I squirreled a copy of this away for future reference.

 

[Hell-on-a-stick]

Thanks for the article. I just ordered 2 kits a unicolor and rollei from freestyle. I have been dev'ing black and white for about a year and would like to try my hand at color, I went to the Rocky mountains and shot 30 rolls of c-41 and E-6 to cross process. Any idea on developing times for cross processing? Im amazed at the lack of internet information on cross-processing, bleach bypass and film acceleration. I intend to use these processes, but im having a hard time finding times and temps. There certainly isn't a 'massive dev chart' out there for color users. I'm getting my notebooks ready, should have all that info within the year. Perhaps I'll at least have a chart of my successes and failures and some viable push-processing times for color films by the end of a year.

 

[nickandre]

Everything in color (excluding some steps of the Kodachrome K14) is done at 100 degrees Fahrenheit with the exception of push/pull processing in film chains which cannot change the time. Cross processing means you run the film through a different process at specification. For example, if you want to run E6 film in C41 process you simply act like it's regular C41 film. This process gives you weird images, depending largely on the type of slide film used. I have never tried it. The times/temperatures don't change. Bleach bypass means you don't bleach, it will give you higher contrast and lower saturation. For push processing you extend the C41 time by 30 seconds for each stop you wish to gain. This is all very standardized between films.

Temperature is most critical in the color development stage because it changes how the CD interacts with the dyes. The temperature is less critical with the B+W developer (in E6 processing) and not critical with bleach and fix. I'm not entirely sure about washing at different temperatures but I assume that the wash is less efficient at lower temperatures. You have to be careful not to cause reticulation by changing temperatures too rapidly. Kodak does state that the Bleach and Fix steps can be carried out down to 70 degrees F, however you might consider extending the time of the bleach to ensure bleach to completion.

 

[Mick Fagan]

Peter de Groot, with C41 processing, the time is about the shortest time of any film processing, as such, you should aim to be as accurate as possible with the developer time, along with the temperature.

Even a little more time can make quite a difference, as can a little less. To push process C41 one stop, you only add 30 seconds, so you can see that if you somehow add 15 seconds to the developing stage, you are effectively push processing ½ a stop.

To ensure that my C41 development time is as accurate as possible, I use a stop bath of 2% Acetic acid solution, then I continue with the bleach step.

I would suggest that you don't run a stabiliser solution through rotary processing, you will end up with very hard to clean tanks and reels.

In fact for C41 stabiliser I take the film off the reel and drop it in curled up, or in the case of sheet film, into a tray, using gloved hands to carefully agitate and then pull out to hang up.

C41 is very easy.

Mick.

 

[Sirius Glass]

I would suggest that you don't run a stabiliser solution through rotary processing, you will end up with very hard to clean tanks and reels.

Jobo specifically states not use PhotoFlo for black & white film nor stabilizer for color film in the rotary tank. Put those solutions in a beaker and immerse the film in the beaker instead.

Steve

 

[michaelbsc]

I would suggest that you don't run a stabiliser solution through rotary processing, you will end up with very hard to clean tanks and reels.

Jobo specifically states not use PhotoFlo for black & white film nor stabilizer for color film in the rotary tank. Put those solutions in a beaker and immerse the film in the beaker instead.

Steve

That seems odd to me. Phototherm has a supply line connection for them, obviously expecting them to be in the processor.

Since Photoflo is nothing more than soap, why is it hard to clean? A good warm rinse seems to work fine for me.

 

[Mike Wilde]

Good article, minor quibble

The temperature is less critical with the B+W developer (in E6 processing) and not critical with bleach and fix.

Actually for E6 processing the temperature and time of the first developer is quite critical, as it sets the density of the resulting transparency.

As to re-using chemistry, I too do this, but strive to re-use within a day of the first run. Do not run the first pass, then sit the partly used chems around for a few weeks, and run the second pass at 3:30 and expect first class results.

Try to save up exposed films, and process them within a relatively short period of time.

 

[Sirius Glass]

That seems odd to me. Phototherm has a supply line connection for them, obviously expecting them to be in the processor.

Since Photoflo is nothing more than soap, why is it hard to clean? A good warm rinse seems to work fine for me.

They state that Phototerm is not to be used in the Jobo.

PhotoFlo is not soap; it is a surfactant. There is a difference. Look up the long threads about using soap instead of PhotoFor or Phototerm.

Steve

 

[fotch]

What is Phototerm ?:confused:

 

[michaelbsc]

What is Phototerm ?:confused:

I'm not sure. I was talking about Phototherm, the rotary processors.

 

[fotch]

It was Steve's pose "They state that Phototerm is not to be used in the Jobo."

He must of meant PhotoFlo?

 

[michaelbsc]

Back to my original point, my Photherm processor has hose connections for both PhotoFlo and stabalizer. So clearly they're expecting the chemicals to be inside the processor.

Not being familiar with the Jobo equipment, I cannot understand why the manufacturer would dissuade the user from allowing them inside the drums. Perhaps there's something about the Jobo design I fail to get.

 

[Sirius Glass]

It was Steve's pose "They state that Phototerm is not to be used in the Jobo."

He must of meant PhotoFlo?

I meant any surfactant for black & white, like Phototerm or PhotoFlo, and any color stabilizer.

Steve

 

[nickandre]

When the color film dries, it must have a bacteriostat like formaldehyde within the gelatin of the emulsion or it will be eaten by small microbes. B+W film does not need this because it has silver within the emulsion which prevents bacterial growth, whereas the silver has been removed from color emulsion. If you use only photoflo, you run the risk of fungus things and bacteria things eating your film unless you add formaldehyde. I find that kodak final rinse mixed with distilled water will leave the film spotless.

The B+W developer in E6 is temperature critical but only +/- 1 degree, as opposed to a color developer which requires greater precision (1/4 degree) to ensure proper formation of the color dyes with proper curves.

I process only one shot developer and fix with films I care about (most films.) Developer is cheap. I store them in glass bottles (2x250, 1x500ml, and 3x1000ml mixed from a 4 liter batch) such that I can always take out one, two, or four films worth and be able to decant the developer such that none is exposed to air. It will last many months in this manner (a year? maybe longer. I'll report if some of my developer goes.)

 

[Hell-on-a-stick]

I have recently attempted this sort of processing. Its not as difficult as some have said, but it is quite exacting. If you don't have your work-flo down, you're going to end up with bad negatives. I've used Unicolor, Tentenal, Arista and Rollei/Compard C-41 chemistry. Each batch of chemistry has been different. I have received some SEVERELY botched bleach from Rollei in the mail that was old and crusty, I've also experienced Unicolor kits to be ULTRA strong for the first few rolls and they push the hsll out of the film, then as they exhaust they begin to develop perfectly.

I think that the solution, as many have said, is to purchase only Kodak or Fuji chemicals, even though they are in large quantity and harder to come up with the money for. Thats my biggest issue to date. Money.

My only real advice to anyone who would like to try this technique on their own, is to first practice with your tank, water and thermometer before you buy your chems. Figure out whether your tank is going to cool off 3 degrees sitting on your kitchen sink or darkroom counter. Do your homework. Figure out what you've got to do to make that temp of 100F possible for 3 minutes and 15 seconds. Each environment is different. Your bathroom darkroom is at a different air temperature than your bedroom and your kitchen sink. Don't get distracted. Color film is also, at least in my experience, relatively sensitive to agitation. I find that most 100 speed films in black and white are not as sensitive as some of the fujifilms that I've developed. A bit too much agitation and youve got a nasty purple mask to deal with in the enlarger, rather than a pale orange one.

All in all, this has been a great journey for me, even though it was somewhat frustrating. Still, I have a tendency to find overdevelopment errors, temp errors and such as the seasons change and the temps in the house drop or rise. Still, its completely worth it to be able to set those negatives on the light box and get the loupe out and examine your own labor. Thats the thing. Doing it yourself is much better than having to blame someone else's incompetence. Its always better to make your own mistakes and achieve your own victories.

 

[Mike Wilde]

home mixed c-22 bleach is great for c-41; it bleaches in about 2.5' at 38C for me, and can be reused and replenished, and is stable when kept in glass in a cool dark place. Filter it after every dozen rolls; it gets very black.

I mix it 80g K Ferricyanide and 20 g K Bromide per litre, but I have seen other formulae where these weights vary somewhat. I would mix 45ml of fresh into the working to keep activity constant, and discard when a litre of replenisher has gone in was my rule.

I found a ton of e-6 bleach and have been using it up for c-41 at 6' 38C for 25 rolls unreplenished. When it is gone I will be back to c-22.

 

[Photo Engineer]

Remember that the C22 bleach is so strong that it can oxidize some components of C41 films. So, be careful! C41 films contain some level of antioxidants to preserve the dyes. Also be careful when using the bleach because you must stop, clear and wash after the developer and before using the bleach. You must then wash again before going into the fix.

PE