Watch a dozen photographers on You Tube and you’ll get a dozen different answers to this question. But just how many rolls of film can be developed from a C-41 Kit?
For the purposes of this discussion, I’ll be referring to the Unicolor 1 Litre Three Step Kit. There are many arguments against and for kits that contain less or more steps but those discussions are for another time. For now, I just want to chat about capacity.
Just in case it wasn’t totally clear, there are two main factors in how long a kit will last. The first is how many rolls of film, and the second being how old is the kit? There are of course many other considerations, like storage bottles, and the type of water used, but these have the most impact, unless you’re storing your chems in large saucer pans?
The short answer is: it’s up to you. But I’m here to say that you should error on the side of being conservative, and in that case it’s about 8 rolls of film, of either 35mm (36 exposures) or 120. Here’s my reasoning.
You have gone though a lot of trouble to shoot film. These days, film is expensive. Kodak Portra is easily twice the cost it was a few years ago. You buy Portra or Ektar or CineStill 50D or whatever for the highest quality results. You went though the trouble of using distilled water to mix the chemicals, and then used a temperature controlled bath to ensure the development was precisely 102F. Why then would you continue to use a developer past the recommended amount?
Here is what colour developer looks like freshly mixed
And this is what is looks like after 8 rolls of 35mm film. Not all of them were 36 roll films either.
If you’re new to film and want to practice, if colour and exposure isn’t as important as the experience, if you’re the type to leave the dust spots on your final image, this may not be the blog for you. What other people call happy accidents I call a pain in the ass. The goal should always be to strive for a clean well exposed image with colours true to the film stock. You need to know the rules to know if and when to intentionally break them and you should be able to repeat whatever unique aspects of a photo you love if you want to be able to call it your own style.
When is it okay to bend or break the rules? I mean in the strictest sense anytime, but in my experience I’ll push the limits of the kit if I know I shot something mundane, or if I found a roll in a thrift store camera and I want to see what’s on it. The truth is though I don’t shoot that much colour, and so when I do, I want peak results, especially lately when I don’t even want to bother with the unpredictability of expired film.
Some people will want to do a side by side, and hey, you’re more than welcome to. Shoot a full roll of the same thing, snip off a bit, develop that with the first roll, store the rest in a tank, and snip and test again every 5-10 rolls. For me, as it's said in the movie Tommy Boy, "I know that I can get a pretty good look at a t-bone steak by sticking my head up a bull’s ass, but I’d rather just take the butcher’s word for it."