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I've been developing B&W negatives at home for several years now. I also live in a city where there are no C-41 labs left, so I'd have to ship my film to be developed, adding extra cost (more than the cost of rolls themselves).

So I did some research and found C-41 isn't much different from B&W (dunk the film in a series of baths), save for the tolerances of temperatures, particularly in the developer (a non issue for me, since I can easily build a very accurate, PID-controlled water heater without much complication).

The problem is that there is no "user friendly" C-41 kits here in Argentina. All I could find were Kodak chemicals, designed for commercial use. These are the catalog numbers available:

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(REV: developer, RELL: replenisher, BLANQ: bleach, FIJADOR: fixer, INICIAL: starter)

The chemicals are not terribly expensive, just $5-$8 USD each, except for the bleach which is very expensive, nearly $100! I've been reading some kodak PDFs and it seems it's not terribly difficult to mix them.

Is it worth it to try doing it with these? Do the concentrates last at least a couple of years to justify the cost of buying "commercial quantities"?

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These formulas are for use in a continuous film machine. As such they are replenisher solutions, not working tank solutions. Mix each according to directions to make a replenisher solution.

To make a developer working strength solution - To make 1 liter - 763ml developer replenisher -- 207ml water --- 30ml starter.

To make a bleach working strength solution - To make 1 liter - 880ml replenisher --- 80ml water - 50ml starter.

Use fixer and rinse same strength as replenisher.

It is possible, but difficult to make small quantities of replenisher strength solutions from these kit concentrates. You measure each of the supplied parts (A and B etc.) and then break down the needed amounts to make a smaller batch. Unmixed concentrates have a longer shelf life than the mixed replenshers.

Also, the purpose of the starters is to season the replenisher solutions so they chemically match the activity of a working tanks that contains the byproducts found in a working continuous tank solution. The developer starter adds the restrainer which is bromine. The bleach starter adjusts the pH to that of a working tank.

Take care measuring solution volumes and you will be OK. Best if you develop a sacrificial roll first to test your results.

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  • \$\begingroup\$ I called the supplier and they told me the starter isn't really needed. I know it's not "really" needed as in "it will develop anyway", the question is, what are the effects of not using starter? Will the first few rolls of film come overdeveloped until the solutions "season" by the film itself? \$\endgroup\$
    – hjf
    Jan 9, 2020 at 14:33
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    \$\begingroup\$ The developer starter is a restrainer. Omit the starter and the developer will be somewhat aggressive, plus the base fog level will be elevated. The bleach starter sets the pH to that of a seasoned tank. The dyes in the film are "leuco" meaning hidden. These blossom during the process forming vivid dyes. The cyan dye is somewhat stubborn, it will not blossom or may revert to the leuco state if the pH is wrong. While you might accept substandard developer activity, you won't like it if the cyan dye is substandard. \$\endgroup\$
    – Alan Marcus
    Jan 9, 2020 at 14:52
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    \$\begingroup\$ The developer will season itself after a several rolls are treated. If you will accept substandard work till the developer seasons, then that up to you. The bleach solution, without the starter, yields leuco cyan dye, the results are "cross-over" densities. The shadow and the highlight color balances will be difficult if not impossible to correct on the enlarger (red/cyan) hue error. \$\endgroup\$
    – Alan Marcus
    Jan 9, 2020 at 15:05
  • \$\begingroup\$ excellent answers. I found someone online selling pre mixed chemicals, ready to use, in small bottles. According to them it's prepared just before shipping to guarantee freshness. I couldn't get them to tell me if they're using the starter chemicals or if they're just using the replenisher. These sell for $15 for 1/2L instead of the $130 required for the Kodak 5L kit. \$\endgroup\$
    – hjf
    Jan 9, 2020 at 15:14
  • \$\begingroup\$ Unrelated to this, I use kodak TMAX RS developer straight from concentrate. The part B is only 15mL. To make 500cc of developer, 1.98mL of part B is required I use an insulin syringe to measure the concentrate. The full volume of the syringe is 1mL so it's easy to dose in 0.1mL increments. HC-110 I also measure with a syringe and don't worry about the "thickness" of the syrup. \$\endgroup\$
    – hjf
    Jan 9, 2020 at 15:23
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C-41 is a standardized process. Regardless of where you obtain the chemicals, the process and times are the same – developer, bleach, fix. Whether to pre-wash or wash between steps is personal preference.

The main variation between kits is whether the bleach and fix steps are combined or separate. When combined, the solution is referred to as "blix".

I have no idea how long the concentrates last. However, they're likely to last longer if stored in a refrigerator.

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I suggest you consider the Cinestill CS41 pack in powder form as a possible alternative.

I have not tried it myself, but it seems as a better alternative than adapting the commercial kit to home developing conditions.

enter image description here

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  • \$\begingroup\$ This kit is not available in Argentina and it's strictly forbidden for individuals to import any sort of chemicals. It's really very hard to justify importing "white powders" no matter how good of a reason you might think you have. \$\endgroup\$
    – hjf
    Jan 10, 2020 at 14:21

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