The Darkroom
Processing Medium Format C 41 Film

Processing with C-41 is relatively easy to perform. The chemicals involved are not overly sensitive or difficult to work with. In fact, even the time and temperatures involved are not real critical. If the time and/or temperature are accidentally allowed to vary a little, the resulting negatives will most likely still be within a range that can be correctly printed by adjusting the exposure/filter-pack on the enlarger. However, if you want negatives that are absolutely correct and consistent, then it is important to be equally correct and consistent in your processing methods.

Today we are in a period of time when there are several formulae of C-41 bleach being used in the marketplace. The old formula of bleach was a hardy, oxygen-loving, solution that was easy to work with. The new formula of bleach (currently used by Kodak) is very different. Because of that, there will be constant references to both types of bleach in this article. So, read carefully. Depending on the specific brand of chemicals you are using, slightly different procedures are recommended.

About Chemical Brands.
I'd like to tell you that all the various brands of C-41 chemicals are pretty much alike, but that is simply not true. Kodak Flexicolor C-41 chemicals will produce the lowest contrast level available on the market today. Almost all other brands will produce negatives that will be higher in contrast.

Now, to be sure, the contrast difference isn't a lot. But, it is there. Personally, I prefer to expose and process the negative in such a way as to capture the greatest possible amount of detail in the negative, especially the shadow detail. Shadow detail is increased by 1) slightly overexposing the negative on the camera, and 2) by using a low-contrast developer, like Kodak's Flexicolor. Then, when printing the negative, if I want a print with greater contrast (sometimes referred to as color saturation) I can always elect to print on a higher contrast paper, such as Kodak's Ultra.

C-41 chemical kits typically contain a developer, a bleach, a fixer, and a stabilizer. Some companies combine the bleach and the fixer into a single, "blix" or "bleach/fix" solution. Some companies don't include the stabilizer in the kit. Do not be fooled. All C-41 film will have a longer life if you will use a stabilizer.

Currently, C-41 film that has been properly processed, washed, and stabilized can be expected to last for 70+ years if stored in a cool, dry, dark place.

Kodak, Beseler, Jobo, Unicolor, and others all make perfectly fine C-41 chemicals.

2-Step C-41 Kits. There are several brands of 2-step C-41 kits on the market where the manufacturer has combined the bleach and the fixer solutions into one solution. There's nothing wrong with the approach. These kits work just fine with all current C-41 films.

However, as I mentioned earlier, I have not found any C-41 developer that produces quite as low a contrast level as Kodak's Flexicolor Developer. This becomes important when you are trying to squeeze every bit of possible detail out of the image. For example, when shooting wedding pictures, you frequently have a picture of a bride in a white dress standing next to a groom in a black tux. Such an image requires that you have the maximum range of tone values if you are going to see the delicate white highlights in the dress and the rich, dark shadow tones in the black tux. The color negative of such a picture needs to be processed in as low a contrast-rendering chemistry as possible.

Most brands of C-41 chemicals (other than Flexicolor) are designed for processing snapshot-type pictures where the customer frequently wants rich, snappy, high color saturation (even at the sacrifice of some tone value detail).

Uneven Wetting In Rotary Drum Processing. When processing in rotary drums there is the special problem of uneven (initial) wetting of the film with the developer. Jobo has designed a method of introducing chemicals into the drum, while the drum is in actual rotation, as a technique of dealing with the uneven wetting problem. It's a good method and certainly helps. It is called the Jobo "Lift." If you have a "Lift" on your Jobo processor (or, if you are using a Jobo AutoLab processor), then you can introduce chemicals to the film while the drum is in rotation. If you don't, then you cannot. Given a choice, always use the Lift and introduce the solutions to the film while the drum is in rotation.

Processing Without The Lift. If you do not have a Lift on your Jobo processor or you do not have one of the Jobo AutoLab processors, then I suggest that you alter the process itself, as a way of dealing with the problem of uneven initial wetting. Since the developing action that takes place during the first few seconds is critically important to uniformity, it is necessary to find a way to make what happens during those first few seconds less important. The easiest way to do that is to extend the total time of the development cycle so that the first few seconds are a less significant portion of the total time. If the total development time is to be extended, then the development temperature has to be lowered to offset the effects of the time extension.

Therefore, when using Jobo processors without the Lift or other types of processors without a Lift-like mechanism, I recommend that C-41 processing be done at a temperature of 86°F for a base-time of eight minutes. Those processing conditions have been confirmed as valid through the use of Kodak C-41 Test Strips.

C-41 Test Strip. Kodak, Fuji, and others make special little strips of C-41 film that have been pre-exposed at the factory. They are packaged (about 50 per box) with a single, "reference" strip that has also been processed at the factory.

In practice, you place an un-processed test strip in with your film when you are processing C-41. Then, later you can take density measurements of the patches on the test strip to determine if the processing was performed correctly. You can compare the measurements of the strip that you processed with the measurements of the reference strip.

This is usually done only if you are operating a large processing machine that uses chemicals which gets replenished or if you are interested in monitoring the way a particular brand of chemicals perform.

The test strips cannot be "read" by just looking at them or visually comparing them to the reference test strip. You will have to take densitometer measurements in order to be able to tell anything from them.

One-Shot Processing. One-shot processing for film, on a Jobo processor, is only cost-effective in Jobo's newer-designed drums and reels (black colored plastic) where the diameter of the drums and reels is larger than the older, original design (white colored plastic). This newer design of reel is available for all of the Jobo processors.

The newer, larger diameter, black colored, plastic reels are identified as No. 2502 Duo-Reel. The newer drums are identified as the 2500 Series Tanks.

With the older drums and reels, due to their smaller diameter, it was necessary to use more solution than what was needed for one-shot processing in order to adequately submerge the film.

The older, smaller diameter, film drums are identified as the 1500 Series. The reel (white colored plastic) is identified as the 1501. It is what Jobo used to call a Duo-Reel. These reels can also be used in the real old 4300 Series of drums that are now out of production.

With the newer drums and reels, due to their larger diameter, the film lays near the outside edge of the drum, where much less solution is needed to adequately submerge it. Thus, one-shot processing is practical, since most of the capacity of the solution is consumed during the process--with very little wasted solution.

About Reusing Solutions. With the older formula of bleach, it was relatively easy to save the solutions and reuse them. The new formula of bleach makes this a lot more difficult. Therefore, I no longer recommend even trying to reuse C-41 chemicals.

Pre-Wetting Color Film. Don't. Don't ever. It's a no-no. Pre-wetting is a valid technique of dealing with the excessive agitation of rotary drum processors when processing black and white film. The Jobo AutoLab processors automatically include a pre-wet cycle when processing black and white film. Those processors do not provide for such a cycle when processing color films.

Preheating Film. Yes, do preheat film. Load the drum with the film and reels, and place it on the Jobo processor to turn in the tempered water for several minutes to bring the dry drum and dry film and reels up to the proper operating temperature, before introducing the developer.

About Stabilizer Baths. Many people complain that their plastic Jobo reels get "sticky" after having submerged them in stabilizer baths (E-6 and C-41). As a result of such complaints, Jobo now suggests that you remove the film from the reels, and not put the reels into the stabilizer. My response: horse feathers. I have been using the same plastic Jobo reels for over 18 years. They are not sticky. I always submerge them in the stabilizer bath. I also always rinse the stabilizer bath off of them with lots of fresh, running water before letting the reels air dry. I never let stabilizer dry on the reels.

In fact, after that, you won't even be able to load that particular roll of film onto even a dry reel until the wet spot on the film dries first.
Never pour stabilizer solution into the throat of the Jobo Lift mechanism. Remove the drum from the Jobo processor and set it up on its end. Then, pour the stabilizer solution into the drum. Slosh the reels around in the stabilizer for a few moments, remove the film, and hang it to dry. Immediately rinse the empty reels and the drum with lots of fresh water.

Water Rinse After Chemical Steps. After you pour the chemical out of a rotary processing drum (during routine film processing), there is lots of it remaining behind, clinging to all the various surfaces inside--the reels, the film, and the walls of the drum. This all adds up to a substantial amount of residual fluid that will contaminate the next chemical that is poured in.

Carry-over of the bleach solution into the fixer is not, and has never been, a problem. While it is a contamination (of sorts) it does not affect the performance of the fixer. It will cause the fixer to turn a brown color.

Using a water rinse after the bleach step does no harm and definitely keeps the fixer from getting contaminated. I always use a water rinse but, in truth, I suppose it isn't necessary.

About Film Squeegees. Do not use a squeegee on your film. I have never found a squeegee that will not ruin film eventually. Almost all squeegees will work OK when they are new. But, after being used a little, the leading edges of the rubber blades begin to wear a little which will cause the squeegee to impart tiny, thin "burnish" lines on your film.

Such burnish lines produce real damage to the emulsion that cannot be corrected.

When I remove my film from the stabilizer bath, I hang it in film clips, then with my bare fingers, I make one, gentle, smooth wipe down of the film. All I am trying to do is to remove the excess fluid, and stabilizer foam, so that "runs" will not form as the film dries.

About Drying Film. If I have processed 4x5 sheet film, when I remove it from the stabilizer, I place the dripping wet sheets in 4x5 stainless steel film hangers, then direct a gentle flow of tap water from a hose over the sheet. I use just enough water to remove the foam of the stabilizer and not enough to really wash off the residual stabilizer. Such "rinsing" with a small stream of water from the tap does not wash off the thin film of wetting agent that will be clinging to the film as a result of the stabilizer bath as long as you don't over do it. Remember, you are just rinsing off the foam--not "washing" the film. I then hang the film to air dry.

You can use a household hair dryer to force-dry the film if you are in a hurry to work with it.

About Water Marks. If you mix your stabilizer with distilled water and squeegee the film as I have described earlier, you will not have water marks. Water marks are dried minerals that have been left behind when the water evaporated. Distilled water does not contain dissolved minerals. Dispose of your stabilizer bath when you dispose of the other chemicals and you will always be using stabilizer that is fresh. Old, excessively used, stabilizer gets crud in it that will remain behind on the film in the form of water marks. Most brands of stabilizer turn pink in color as you use them. The more you reuse them, the darker color of pink they become.

About Freezing Solutions. I am frequently asked about how to store the solutions to improve their shelf life. The C-41 developer is like any other color developer in that it does not have a very long shelf life--especially after it has been mixed.

Your best indication of whether or not you should use the developer is its color. When C-41 developer is first mixed, it is almost water clear with maybe a very slight amber color. As it ages it turns darker and darker. If the developer gets to the point where it has about 10-15cc of dark amber color to it, toss it. In other words, when it starts to take on some noticeable amber tint, don't take chances with it.

You can add inert gas to the top of the storage bottles to replace the air. That will help a little to slow down oxidation. Remember though, most plastic bottles are made out of high-density polyethylene which allows a lot of oxygen to migrate right through the side of the bottle. Glass bottles are best. Polypropylene is next best. Polypropylene is the type of plastic that most kitchen dish pans are made out of. It has a slippery, wax-like, feeling and is very flexible.

High-density polyethylene is what the Jobo plastic storage bottles are made of. This type of plastic is less flexible and has a smoother, dryer, feel than polypropylene.

Store mixed solutions and concentrates, as cool as possible, in full, tightly closed bottles. Glass bottles provide more of an oxygen barrier than plastic bottles. I used to store the developer in the refrigerator. That worked fine until one day when the refrigerator got too cold and the bottle froze. I tried processing some film with the frozen developer and it worked. I've been freezing C-41 developer ever since.

I use a plastic one-liter bottle and fill it to within about 3/4" of the brim. I tighten the cap and put it in the freezer. The bottle will swell up a little as it freezes. So far, I've never had a bottle actually rupture. The plastic seems to stretch a little.

Do not use glass bottles if you are going to freeze the developer. A glass bottle will crack when the solution freezes. When I'm ready to use the solution, I remove it from the freezer and let it warm up slowly to room temperature. There is always a white precipitate in the bottom of the bottle. I simply shake it up and ignore it.

When I'm ready to pour the developer onto the film I shake up the bottle so that the white precipitate gets uniformly dispersed just before pouring the developer into the film drum. I've never had any problems. I've never tried freezing any other brand (than Kodak) of C-41 developer, but I would expect them to all act about the same.

As for the fixer, bleach, and stabilizer--they have excellent keeping properties. I usually buy C-41 chemicals in one-gallon individual concentrates. I mix the whole gallon of the bleach, fixer, and stabilizer. I've never had any problems with keeping them for up to eight or nine months. With the older formula of bleach, I would always shake it up real vigorously just before using it. The older formula of bleach used to like to have lots of oxygen. That is no longer true with the newer bleach formula. Don't shake up the new stuff.

Don't shake up the fixer. Fixer isn't so fond of oxygen.

Special Exceptions.
When all else fails, follow the manufacturer's instructions. Manufacturers are always coming out with some new wrinkle of product to allow them to better compete with other companies.