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Color Darkroom

by Jerry Sparrow

I noticed there was a comment about the lack of information in print with regard to color darkroom work. I have observed this myself and have been somewhat surprised. However, having been a professional for over twenty years I was not in utter shock. In this article I am going to try and deal with some of the reasons these materials are so uncommon. I will also describe some of the basic color darkroom theory, techniques and equipment.

The lack of information

Most people are reluctant to begin working with color in their darkrooms. Some of this has merit and some of it doesn't. Personally I feel to start into color requires a great commitment on the part of the photographer, both in terms of time and cash. Color darkroom work is quite expensive. Not only in the materials involved but also in the equipment required to produce quality work. Few people have the resources to create a truly top notch black and white darkroom, let alone a color one. Even if they do have the money color photography is a multi-faceted discipline that requires a great amount of attention to detail. While I believe their are many talented individuals out there that can do color in their own darkrooms I think that many pro photogs try to hold these secrets close to the vest, and that is a shame. Also much of the information for color work is available from Kodak and other manufacturers web sites, and prior to the advent of the world wide web they were always just a phone call away. Therefore many professionals felt it unnecesary to re-invent the wheel as it were since most of the technical data was already available. For instance at the link below You will find a vast array of technical information on color darkroom practices and techniques under the "Technical Publications" heading:

Kodak Technical Data

I also recommend going to this next site to get the most information on Kodak C-41,
the chemistry used for color negative film::

Kodak C-41


If you scroll down the page you will see many processing guides including the ever famous Kodak Z manuals used in labs all over the world to monitor and control their processes. Unfortunately this un-willingness by pros has made it dificult for amateurs to learn the techniques very effectively on their own. I am one pro who hopes to make up for that, starting with this article and also with the book I have been working on for some time called "The Fifteen Minute Photographic School" in which I take photography and break it down in short sections with lab exercizes and experiments.

Basic color theory

Color is not a magical process that is achieved by waving a magic wand over the film or incanting long lost and forgotten spells, but it is different. Color film instead of having one layer of emulsion has three, all of which are basically black and white film emulsion with one key difference. Each of these layers are made sensitive to different wavelengths of light by the introduction of carbo-cyanine dyes in the formulation of the emulsion; different dyes deliver different spectral absorption characterisitcs. The first layer is the blue sensitive layer. This layer is first because all film is inherently sensitive to blue light, and the blue emulsion requires the least amount of filtration. On top of the blue layer is an Ultra-violet filter. Next we find the green sensitive layer, this layer has a yellow filter layer above it and lastly we have the red sensitive layer under a red filter. Unlike black and white film, which has the silver in the emulsion reduced to metallic silver in the development process, color film actually has the silver halides that were exposed to light replaced with color dyes that correspond to the color layer. For example, when the film is processed the red layer has all of it's silver halides that were exposed to red light replaced with red dyes. The intensity of the dyes introduced are directly propotional to the amount of exposure the layer received. Once the film is processed the varying intensities in the three layers sandwiched on top of one another give all the different hues present in the original scene. Once developed the film is then placed in a bleaching bath which removes ALL of the silver in the film. leaving only the dyes.
There are two basic color systems in use today, these are the additive and the subtractive color systems. In the additive color system we work with Red Green and Blue. In the subtractive system we work with the colors Yellow Magenta and Cyan. the two systems derive their names by the manner in which they combine the colors. The additive system can be described as the combination of the three basic colors to achieve any color required. If for instance we add Red and Blue together in equal amounts we will get Magenta a sort of purple color. By varying the amounts of red and blue we get all the colors that reside in the spectrum between red and blue. The same is true with regards to the combination of blue and green and green and red. The interesting thing about the additive system is that if we combine all three colors we get white. This is because white is the presence of all colors.


The subtractive system on the other hand works by the act of cancellation of different light (or subtraction if you Will). If we place three lights, each with a different filter in front of them, one with a magenta filter one with a cyan filter and one with a yellow filter, so they can shine on a wall in a manner in which all three lights will intersect with each other we will see the following. In the area where yellow and magenta combine we will see red at the intersection, likewise we will see green at the point where cyan and yellow combine and finally we will see blue at the point where cyan and magenta combine. Just as there was a unique quality in the additive process there is an even more bizarre quality in the subtractive. If we combine all of the colors of the subtractive process together we will achieve black at the point where all the colors intersect. This is due to the fact that the three colors cancel each other out, as it were, and yied the absence of all color, or black.


This brings up the point of complimentary colors. Complimentary colors refers to the manner in which the two systems interact with one another. For example if I were to print a negative and I found that the whites in the print are too red I can "cancel out" this effect by adding cyan. If you look at the above diagram you will see that Cyan is directly opposite of red and that the two colors point of commonality is black. This is how the cyan is able to cancel out the red. Consequently Yellow and blue are complimentary as are magenta and green. There is an old saying to help you remember. "there is a General Motors Red Car in my Back Yard" GM, RC, BY. Or Green Magenta, Red Cyan, Blue Yellow. I know this sounds trite but it helps me to say this little ditty, ever since I learned it I have never fogotten the complimentary colors.

Equipping the color darkroom

Ok I am sure you are sick of hearing me ramble on about theory. We will now discuss the equipment required for the color darkroom, and which we would probably never see in a black and white darkroom. The most important thing about processing color is temperature control. If you cannot keep your chemistry within 1/4 of a degree of 100 degrees then don't bother. I know this sounds rediculous, but there is a reason. Color materials unlike black and white can have the color balance shift by even a tiny change in the developer temperature. This is because the spectral dyes in the emulsions absorb the transfer or replacement dyes from the chemistry correctly at only one temperature. In the case of C-41 that temperature is 100 degrees. If this tolerance isn't met then an object that was scarlet in the scene may come out pink in the final print. This means we need a way to control that temperature accurately and consistently. There are a couple of ways to do this and both are rather expensive. One is a water regulator valve. the water regulator valve is a device that accepts both the hot and cold water from your supply and has a large round dial by which to control the mixing of the two. The assembly also has a large round dial thermometer to monitor the temperature with. These valves are quite accurate and as such are quite expensive. They usually run around $250.00. The second way, and by far the most accurate, is to use a heated recirculator pump designed specifically for photographic purposes. These units take the water from the sink, regulate the temperature, and return it to the sink. These units cost about $500.00. In both systems the photographer places his developing tanks in a water bath in the sink and thus is able to maintain a constant 100 degree temp.
The color enlarger is quite a bit different than the black and white enlarger. On a color enlarger you have a color head above the negative carrier. This color head has three filters in it. Usually these filters are of the subtractive variety, but in rare cases you will see one with additive filters. these filters are referred to as dichroic filters. These filters are also usually graduated from dark to light in each of the respective colors. Thumbwheels or dials are usually used to "dial in" the filter pack thus changing the amount of gradation used in the printing process. The graduations for this technique are usually in divisions of 5 ranging from 10 to 90. These numbers represent the number of an individual filter. For example if I were to use individual filters I would have a Magenta filter of 25 (CP25M) and a cyan filter of 10 (CP10C) and a yellow filter of 15 (CP15Y). This would be my filter pack for a specific negative on a given type of paper. The thumbwheels on the color head of the enlarger make it possible to just dial in the setting and avoid the hassle of finding color filters and sandwiching them together then placing them in the path of the negative. From this discussion one thing may appear obvious. It is not entirely necessary to have a color head on your enlarger. One could purchase an inexpensive or even used set of color printing filters and use them with a good black and white enlarger. While this would be quite a bit more difficult and time consuming (not to mention giving you several more items to clean in the print path) than using a color head it works just as well and costs a lot less.


The last thing that would be noticibly different in the color darkroom are the tanks for color processing. Instead of using one daylight tank you would want to use 6 seperate open tanks in complete darkness with a good quality film washer and timer.

Doing the work

Well we are finally here, the point where the work actually begins to take place. We will start with the actual processing of the film. To process C-41 or color negative films in Kodaks C-41 Flexicolor chemicals the following are the steps to employ.
1. Establish your sink line. Place the tanks in the sinkline in the order of use,(Developer, Bleach, wash, Fix, wash, Stabilizer) and bring the water bath to 100°F.
2. Turn out all room lights! And load the film on the reels. Place the reels on a spindle rod so you can agitate the film by raising and lowering it with the spindle.
3. Set your timer for 3:15 and place the film in the first tank or developer. Then agitate for 5 seconds at each 30 second mark.
4. Set your timer for 6:30 and place the film in the second tank or bleach. Agitate every thirty seconds for 5 seconds.
5. Set your timer for 3:15 and place the film in the third tank or first wash tank. let it wash for the prescribed time with sufficient agitation.
6. Set your timer for 6:30 and place the film in the fourth tank or Fixer. Agitate every thirty seconds for 5 seconds.
7. Set your timer for 3:15 and place the film in the fifth tank or second wash tank. let it wash for the prescribed time with sufficient agitation.
8. Set your timer for 1:30 and place the film in the sixth tank or stabilizer. Agitate every thirty seconds for 5 seconds.
9. dry the film for the amount of time needed from 75 - 110°F.

That is the process in a nutshell. It is not complicated but if you do not have good temperature control it can be frustrating. This is not to say it cannot be done in a daylight tank it just isn't recommended.

Once your film is dry we will want to print it. To print the film place it in the negative carrier and then put it in the enlarger. On your color paper data sheet there will be a basic filter pack setting. For example for Kodak Supra III paper it is recommended that you start with a filter pack of 45M and 45Y. Dial in these settings or place the filter pack in the print path and make a test exposure. The best way to make a test exposure is to place a piece of cardstock over all but a small section of the paper. Set the enlarger timer to 3 seconds and make an exposure. Now move the cardstock a couple of inches over to reveal more paper and make a second three second exposure. Repeat this process until the entire paper has been exposed. By doing this you will make a series of exposures from 3 seconds progressing by three second intervals. In other words 3 seconds 6 seconds 9 seconds etc. This will help you to determine the best exposure timewise for the final print.
Now we will want to processs the test print. I highly encourage you to invest in one of the small tabletop rotary drum paper procesors from Jobo or Doran. With the drum and motor base you can be in business for around $160.00. Again I recommend going to Kodak professional site and getting the processing information for Kodak RA-4 Ektacolor chemicals for the processing recommendations for their chemistry and paper in the rotary tube machine.The link is:

Kodak RA-4 Chemistry



Scroll down the page to find all the information you need for rotary tube, tray and manual tube processing.
Once you have the print in your hands examine it. Determine which of the time swatches gives you the best exposure. Set your enlarger timer to that setting. Next we will color correct the print. The main thing to remember when color correcting is this, go for the whites. Try to get the whites as white as possible, without destroying the proper color of the rest of the scene. Kodak offers a set of color print viewing filters to help you determine the amount of color correction needed, however, with time you will be able to judge this on your own very accurately. If the scene looks overall to be too blue then you would simply dial in a little more yellow to cancel out the blue. Or if it is a little too red dial in some cyan. This is done and the neg is printed again but without the preceding technique of multiple exposure as we already have our time determined. Process the new print and again examine it. Check again for exposure and color balance, making adjustments as needed. This process is repeated as many times as is necessary to achieve the final print. Odd colors such as Aqua may be tough to correct at first, you need to think about the colors that make up these odd colors, and this is the one place that the color print viewing filters can really help. It takes time to master the use of these filters but if you view the white areas and correct for them you should have good results. Obviously this technique is very subjective and is dependant upon ones personal taste, as is most of photography.

Other Processes

While this discussion has focused on C-41 primarily, there are other processes the home darkroom enthusiast can do as well. Such as E-6 for Ektachrome slide films. Again simply follow the above links to the Kodak professional site and download the manuals you need. Also Fuji, Agfa, Ilford and others have processes that you may want to explore. One word of caution though, don't get over-ambitious and decide to try Kodachrome or K-14 at home. K-14 is a very specialized process that only the largest commercial labs with the best trained people can tackle. In fact I would say some seventy percent of all labs in the country send their K-14 to Kodak for processing. Kodachrome uses an automatic processor that actually exposes the film to various wavelengths of light during the process. Keeping a K-14 processor within quality control guidelines is probably one of the most dificult challenges any photo lab could attempt to do. In fact while I was on board the USS Nimitz during my time as a Navy photographer I never saw the Kodachrome machine ever fired up, or for that matter filled with chemistry, even though we had Kodak trained people on ship who could operate the machine.

Final Thoughts

Color chemistry is very caustic, Plastic or meticullously kept stainless steel are the only materials to use around any color chemistry. Also if you do not have a good ventilation system do not work with color. The fumes can be very harmful. Almost all color work must be done in total darkness as color materials are sensitive to almost all wavelengths of light. The cost of color materials are prohibitively expensive. For instance a 1 gallon kit for C-41 is around $70.00. The printing paper seems to be the one thing that is not so expensive B&H photo sells 100 sheet boxes of SupraIII 8x10 paper for around $28.00. Don't get discouraged if your first attempts at color don't come out all that well. Color technique, especially printing, takes time to learn and master. By all means if you have the inclination (and the budget) go for it.
This is but a very brief introduction into color darkroom work, but should be sufficient to get you started. I hope this little introduction has helped, now go have fun!!!

Text and pictures copyright 2001 Jerry Sparrow

Article created 2001

Readers' Comments


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Darren Holloway , December 13, 2001; 01:35 P.M.

Yet another article saying how hard it is to do colour work at home... Sigh... Granted, everything Jerry says is true... Doing C-41 is hard and finicky and far less convinient than walking a block to the nearest processor and paying four dollars to get your film back in one hour.

But home colour printing with RA-4 is pretty simple and forgiving. It is more work than B&W because you have to expose the paper and transfer it to the drum in total darkness, and you have to use a water bath (aka "The Sink") to keep the temperature up, but that's about it.

According to the link above, RA-4 has to process within 1/3 of a degree... But if you're off a little bit (like a degree,) I find that you'll still get a better print than you'd get at Wal-Mart or other cheap one hour lab, if for no other reason than because you're using better paper. And you won't be paying $10-15 for an 8x10 enlargment either.

If you just want to try colour printing out, Tetenal (aka Jobo) makes RA-4 chemistry in 1 litre kits. The only problem then becomes you start having fun and run out of chemistry quickly since you use it once and discard it!

Jerry Sparrow , December 13, 2001; 03:17 P.M.

Darren: Thanks for the input. I am in no way trying to discourage people from printing color at home. Color printing is fairly easy. it's the processing of film that is so finicky, and requires the large outlay of cash. I hope my article in no way discourages people from trying color at home. Just the opposite. I was trying to point out in a very realistic manner that one needs to take extra care and expect to lay out some extra cash. But if done carefully one can achieve excellent results with modest equipment. I was not referring to RA-4 when I was talking about the 1/4 of a dgree tolerance, it was the film I was referring to that has the tight temperature tolerances. I have worked in color labs for a large portion of my life as a quality control specialist and I can attest to the fact that temperature changes cause color shifts. Please everyone ....if you have an inclination to process and print color at home .....GO FOR IT!!!

Steve Dispensa , December 15, 2001; 04:00 P.M.

Besler makes a kit they call RA4-AT that's supposed to work at room temp. You have to calibrate the development time to your desired color balance, but there's a guide sheet that goes from low sixties to high eighties in chemical temp. With this system, if you're in any sort of consistent atmosphere (ie reasonably consistent house heating), temp control gets a lot easier. I never see my chemicals move from 69 degrees, unless I add fresh water for rinse (I usually let freshly-mixed chemicals stand 24 hours in their plastic containers *in the darkroom* before use). Rinse is less sensitive to temp than other steps, so I just set the faucet at whatever gives me 69 degree water and leave it. I have no trouble working with these chemicals for hours in what is probably below-average ventilation.

Be careful who you buy this kit from, though - it has a short shelf life, and I once bought a kit from a local shop that I later found out was many months old. Ugly ugly prints.

Anyway, as I see it, there's at least as much reason to do your own color printing as there is to do B+W. Try dodging with pieces of CP filters or changing filter packs halfway through exposure... the list goes on and on. Or, as pointed out above, just go for nice-looking prints that you really can't get from Wal-mart or even most local camera shops. Custom cropping, consistent color from print to print, optimal balance, etc.

George Jounakos , December 17, 2001; 11:52 A.M.

A few months ago I started doing my own color processing.(film and prints) As long as you can keep your process consistent, your results will be consistent. To be consistent it helps to have the right equipment. (Jobo drum processor or similar) If you don't have the money for the right equipment, wait until you do. The wait will be worth it. I have been using Tetenal chemicals, I'm not saying their the best but so far no problems. Don't be afraid of the Press kit which is powder. It works fine and saves some money. Just a final note: Some professionals comments/input on this site can push the beginning hobbiest away from trying something. While the professional has great skill and knowledge, sometimes after doing something for so many years, a professional starts to look at only professional ways of doing things. There are many hobbiests that do not need 'perfect' results, and if they get any result at all makes them happy. Professionals out there please don't fight with me, it's just a point of view. Besides, think about when you started and that old professional said you were doing something wrong.

Patrick Chase , December 19, 2001; 03:07 A.M.

There is one processing alternative for C-41 which wasn't mentioned in the article: A Jobo CPP-2 or similar low-end rotary machine. They're rather expensive new ($1800 or so with lift kit), but can be had used for $600 (Ebay) to $800 (respectable dealers) these days as small studios with in-house processing ditch them in favor of digital. These machines take care of the temperature control (to within +/- 0.1 degrees C) and agitation, and can be operated in daylight once the film has been loaded into the drum.

Carl Dahlke , December 21, 2001; 05:07 P.M.

I've been working with color printing (RA-4) for about 4 years. The actual physical development of prints is easy if you have a temperature controlled print processor.

The hardest part of learning color printing is not technical control of print processing - it's learning to really see the colors in your prints. I believe that it took about a year before I was really sure at least 80% of the time of the color adjustments I needed to make after pulling the first print from a negative. One tool that was very helpful when I was starting out are the Kodak print viewing filters which provide 3 densities of each of cyan, magenta, yellow, blue, red, and green. With these you can get a very quick idea of how your colors need to be adjusted.

The biggest problem I had with print processing is that it is so mechanical that I kept getting bored and losing track of the processing step I was in. I found one great tool to help overcome the boredom problem, the GraLab 900 processing timer. This timer can be programmed to time up to 8 processing steps and automatically progresses from step to step. I recommend it as a great aid if you are using a processor in which you have to time each processing step yourself.

John Banister , January 29, 2002; 05:51 A.M.

While these words are not directed to anyone intending to be a professional photographer, I would like to say that I've derived considerable pleasure at very little expense from developing E-6 process color slide film with the following equipment: a 600ml graduated cylinder, a dial thermometer accurate to half a degree Farenheight, four 500 ml nylon bottles for chemicals, a stainless two reel developing tank, two stainless film reels for 35mm film, three little aquarium heaters, a three gallon "Rough Tote" storage container, a small changing bag, a half dozen spring loaded cloths pins. My total investment for this stuff was about $125 in about 1990. The stainless steel stuff took up the biggest share of that. It all fits in that storage container when I'm not using it. I usually buy the Tetenal half lieter "E-6 3-Bath Plus" chemistry for less than $20 (for 6 rolls of 35mm), though I'm glad I bought the Kodak chemistry once, because it came with a time table adaptable to different temperatures and times for processing film that's been pushed or pulled. It's not that hard so long as you keep everything the same temperature. Recently, I bought a reel for 120 film that fits in that same tank and used that same equipment to develop 6x6 slides.

Darrell Harmon , April 05, 2002; 05:00 P.M.

I noticed that Ilfochrome (Cibachrome) is not mentioned anywhere. This is a very easy to use process that yields excellent results. Temperature control is about the same as black and white. It can even be processed at room temperature. The paper is expensive. It is available in polyester glossy for about $50 for 25 8x10's or pearl RC for $25 for 25 8x10's. The polyester looks best but I would recommend starting with the RC because you will waste some. The chemicals are $45 for a box containing 2 1 litre kits. The process is P-30. I have printed this in trays before and it worked quite well. All you need to print this material in a black and white darkroom is a box of filters for about $25.

Darrell Harmon

Buck Rogers , September 07, 2002; 01:32 A.M.

Working in the color darkroom for me hasn't been nearly as difficult as the previous comments suggest. I use Besseler's RA-4AT chemistry kit in my basement bathroom cum darkroom (Chemistry works at room temp). The first few prints were even done in trays (and total darkness of course). The most time consuming part is getting the color balance for each type of film that one uses. Once this is done, the process is as simple as (and to me-easier than) B&W printing. The only tweaking is minor color adjustment and endless variations on traditional burning and dodging.

Granted I'm new to color and have no formal training, my prints beat any budget lab Wal-mart prints and even beat out the $10 professional lab D-prints. I've found the amateur oriented machine prints from even pro-labs are seemingly balanced digitally in a way similar to hitting "Auto-levels" in PhotoShop. This sets a color balance the establishes the darkest spot in the frame as pure black and the lightest as pure white. For photos that contain neither of these colors, a custom handprint seems to get the best and most natural results (especially in more neutral contrast photos like portraits). Plus the 8x10 is only about $.50-$1.00 depending on the paper and how many test prints you do. After that, duplicates are only $.30 each (including price of chemistry).

I'm hooked on color printing and look forward to learning gaining more experience. If anyone knows of any references that will accelerate my learning, please let me know.

John Mazza , April 02, 2003; 01:13 A.M.

C-41 Processing

I've been processing C-41 negatives using Paterson's 2-step C-41 kit and have had very good results despite not having super accurate temperature control. I have found that any temperature between 93 and 104 degrees results in little or no noticeable shift in color on my negatives so long as I adjust the development times in accordance with the tables included with the kit. Another positive for the Paterson chemistry is that it is rather inexpensive - a 3 liter kit runs about $25.00 and will process somewhere in the neighborhood of 50 - 60 rolls of 35mm 36-exposure film.

Combined with a film scanner the Paterson kit is the best way I have found to make very high-resolution digital images and 8X10 prints inexpensively and with much more control over the image than using photo paper can provide.

Bud Gray , March 07, 2007; 09:27 P.M.

I am very new to color negative film processing, and I have found that after my first few attempts using a Jobo Press Kit and the stainless steel single-reel tank that I use for B&W processing, that the tank *hemorrhages* chemicals. It has a plastic lid and cap for pouring solutions in. I've lost as much as 30 ml of developer and/or fixer at 38 C.

I have read here and elsewhere that all tanks leak. Is this so, and if so, can I realistically process color film in a small tank environment using stainless? Would switching to plasic tanks do me any good?

Any information would be apreciated, and I apologize if this has already been covered (I have searched to the best of my ability).

Kind regards,

Bud

Rowland Mowrey , March 14, 2008; 10:14 P.M.

A few comments here:

1. No color film has a filter layer above the red layer.

2. Color print and film materials can be processed at other temperatures than 100F. In fact, I routinely do RA4 products at 68F with a simple color correction of about 10Y.

I have posted the actual structure of color negative films elsewhere and I have a series of posts here on color system engineering. I think that the author here should read the explanation of color materials by Chuck Woodworth elsewhere on the internet for a better understanding of the systems.

Ron Mowrey


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