A prospective customer emailed me today about the C-41 kits in the store. They asked about the shelf life of the chemicals involved, and also wanted to know whether developing colour film was really tough and unforgiving, as some people say. I wrote up this reply, and wanted to post it here as well, hopefully it helps out other folks in the same boat:
So first off, about the expiry dates: The C-41 kits contain powdered chemicals, which are sealed extremely tightly in metallic bags, and my understanding is that these will last a very, very long time in that form. Once you expose them to water, then it’s a different story, but I know people who take months to use a mixed kit, and swear there are no bad effects.
The way you store your mixed C-41 chemicals is very important to how long they last, and there are 3 things you can do to make sure they last as long as possible:
1. Keep oxygen out of the bottles. I understand that this is the most important thing you can do. Whatever bottle you use to hold your chemicals, you want to squeeze the bottle before you put the lid on, so the liquid goes right up to the top, then put on the lid tightly. Some people use empty pop bottles, some use special bottles meant for film that let you do this too.
2. Keep the bottles in a dark place. Or just have an opaque bottle.
3. Keep the bottles somewhere cool. My understanding is that you don’t have to go crazy on this and refrigerate them, just try to put them somewhere that doesn’t get too warm/hot.
So for the next question, is it hard/unforgiving to develop colour film:
I know that when I started developing film, I read this all the time – everyone said that Colour was much tougher than B&W. Because of this, I put off doing C-41 for quite a while. However, as time went on, I started hearing more and more people saying it wasn’t really that hard, so I started researching it, and realized it didn’t sound much different. Finally, I gave it a go, and my conclusion was that wow, it was just as easy as doing B&W, and in some ways easier.
In most ways, the home developing process for C-41 (colour) film is just like B&W: You load your film into a tank, and you have 3 liquid chemicals that you pour in, leave a while and then pour out, one by one. The main difference between B&W and C-41 is just that B&W chemicals are kept very close to room temperature, but C-41 developer needs to be heated up, to about 39°C, or thereabouts.
So this sounds pretty daunting at first, but when I actually tried doing it with a thermometer, it was really not that tough. You heat some water in a small tub to about 40°C or 41°C, you put your developer bottles to stand in this water, and you wait for it to reach the right temperature. You might have to fiddle with the bath a bit and add a little more hot or cold water now and then, but it’s really not tough.
If you think you’re going to be doing it a lot, you can get a Sous Vide heater, which have become extremely popular for this use in the last year or so. This is a cooking tool you can clip to your water bath container, and it’ll regulate that water and keep it at the right temperature while your bottles of chemicals heat up in it (you don’t put the sous vide heater directly in the chemicals).
But I want to stress, you absolutely do not need a Sous Vide, or any other fancy heater. You can do everything yourself with just a thermometer. A Sous Vide (or other heater) just lets you set it up, go do something else, and come back to perfectly heated chemicals a while later.
So this brings us to the part about developing being unforgiving. This is the thing that kept me from developing colour film for the longest time: I kept hearing that you had to keep the water temperature within 1 degree in either direction, or your photos would turn out badly. I even read some people saying you had to keep withing 0.5 degrees.
After talking to a number of people, and my own experience, I think this is one of the biggest misconceptions there is. You can be off by at least a few degrees with no bad effects. I actually had a badly calibrated thermometer to start, and developed numerous rolls at 3 degrees off, and I didn’t notice at all, the photos all looked great. Recently, one of the hosts of the Film Photography Podcast mentioned that he had done experiments with developing at 10, and I think 20, degrees Fahrenheit off the correct temperature. He said he went above, and below the recommended temperature, and still wound up with fine photos. (He may have mentioned some extra grain at the extreme temperatures, and I definitely wouldn’t do this on PURPOSE and expect perfect results, but this is extremely interesting to me, and I’d like to try it myself sometime as an experiment.)
And one thing people don’t mention about C-41 temperature too is that of the 3 chemicals you use, only the first one, the developer needs to stay at the correct temperature, and (at least in the Unicolor kits we sell) the film only stays in that chemical for 3 and a half minutes. So you don’t want to worry too much about the developer losing temperature, since after 3:30 or so, you’re moving on to the next chemical anyway. (The next chemical is Blix, which even the Unicolor instructions say can be 10 degrees off in either direction).
There seems to be a lot of things in the film photography online world that aren’t completely, fully documented, and a lot of them seem to turn into games of Telephone sort of. Someone on a message board will say that you should try to stay within a few degrees of the correct temperature, and over the years this will be passed down from msg board to Facebook group to Twitter feed to msg board, etc, until someone is saying “If you don’t get within half a degree of the right temperature, your photos will EXPLODE and YOUR HOUSE WILL FLY INTO SPACE”. The temperature thing is a prime example of this, to me anyway.
Oh and also I wanted to cover why some people consider C-41 developing easier than B&W: With C-41, there is only a single developing time for your kit. It doesn’t matter whether you’re using ISO 100 or ISO 1600 film, whether it’s Kodak, Fuji, Lomography, etc. – it all just goes in the developer (then blix, then stabilizer) for set times. You can mix any C-41 colour films you want in one batch, and it’ll be fine. With B&W this is the complete opposite, and you have to look up times for each film/ISO/developer combination, and you can only mix multiple different films in one batch if they happen to share the same times.
So that’s that, I hope this is helpful. Because I actually sell C-41 developing kits, I always worry that I might sound like I’m biased or something, but I really do believe that it’s just as easy to develop Colour as it is B&W. I actually also sell B&W chemicals, so if I really thought that was an easier process, I’d just say so. And personally, I definitely love that the times are always the same and I don’t have to look things up every time I change film (or developer, ISO, etc), although I know some people really enjoy the process of experimenting with different times and temperatures and whatnot for B&W.