Processing colour slides at home

Note added June 2006: This article was originally written in December 2002, and some of the information in it is now out-of-date. In particular, the availability of small E6 kits is changing all the time, and as camera stores scale back their darkroom offerings, thesy can become increasingly hard to find — even if they are still being made. Your best bet is to purchase from large mail-order shops like B&H, Adorama or Freestyle.

For one user’s step-by-step guide to colour reversal at home (your kit may vary), have a look at

Processing B&W film at home is a no-brainer because it’s very simple and much cheaper and better quality than from a commercial outlet. I have processed E6 (slide film) at home as well. It is not nearly as hard as people make it out to be. The big differences between E6 processing and B&W processing are:

  1. E6 is a standard process with standard times and conditions. No playing around with different developers, times, dilutions, etc. here. B&W by contrast (no pun intended) is much more loose. The E6 chemicals come in kits, no mixing and matching.
  2. Temperature control is much tighter. B&W can be processed at about any temperature but E6 needs to be tightly controlled at 38C for at least the first step. There is room for variation in later steps.
  3. Agitation is more frequent, every 15 seconds or continuous for E6 instead of once or twice a minute for B&W.
  4. The colour slide chemicals go bad far more quickly than B&W do. Count on two weeks, tops, once mixed.

If you are new to developing your own film, do not start with slide film. Master B&W first. Also, my aim here is to rant rather than provide explicit directions. You should get a good book like Basic Darkroom Techniques by Grill and Scanlon to learn the basic steps. These authors describe how to process film at home using easy instructions, with pictures. I’m sure there are lots of other good books out there, but I haven’t seen them.

What you need that you might not already have

Since you already do your own B&W at home (right?), you have most of what you need. Here are some things that may be different:

  • The tank and reels — stainless steel is best because it conducts heat better. In addition, many kits provide only 500 ml of developing solution. This is enough to cover two 35mm reels in a stainless steel tank, but not in a plastic tank. Plastic tanks need about 650 ml for two rolls. (Note: Several people have since pointed out to me that the plastic Jobo tanks can develop two 35mm rolls with 500 ml or less of solution. As far as I know, though, none of the Paterson-style tanks can get by with just 500 ml.)
  • The chemicals — various manufacturers (Tetenal, Beseler, Kodak, etc.) make kits, either six-bath (the traditional E6) and three-bath (a simplified E6). The kits are available in different sizes. I like the 500 ml Tetenal kit, which processes six 36exp 35mm rolls of film (in three runs with two rolls each). There is an offer available from Tetenal for introductory pricing on their 500 ml three-bath kit. I don’t want to link directly to this offer page, but a google search for tetenal 50% off should reveal it. Tetenal is distributed by Jobo in the USA. Otherwise, try your local darkroom supplies store or B&H, Adorama, Freestyle or your other favourite vendor. The three-bath kits cost about US$15 to US$20 depending on where you purchase them. In Canada, the Agfa kits seem to be widely carried — I have seen them on the shelves at Royal Photo in Montreal and at Henry’s in Toronto.
  • The thermometer — you need to be able to read this quickly and accurately to within a fraction of a Celsius degree.
  • The temperature moderating system — you need to be able to maintain the temperature at 38C +/- 0.5C. I use a cheap sytrofoam cooler I bought at the supermarket for $3 and fill it to a depth of about 10 cm with water, balancing hot and cold until I hit the right temperature. The container is well-insulated and keeps things warm so that minimal intervention (i.e. adding more warm water) is required. There will be a temperature drop over the time you need to do the E6 process (which is about 30 mins) but steps that follow the first one are less temperature-sensitive anyway.

While I’m here: a note about Jobo processing systems. Many people read on the Net that a Jobo system is required to develop slides at home. Not true, though I’m sure it helps. For all of you who are wondering what a Jobo system is (I did once): the Jobo company makes a series of processors of varying sophistication that automate some or all parts of the film developing process. At minimum they seem to consist of a system that agitates the tank and a thermostatted water bath that keeps the solutions and tank at a constant temperature. The more complex ones will fill and empty your tank for you, too. They are expensive by home darkroom standards — several hundred US dollars and up. You can definitely get by without one, as I describe.

  • Rubber gloves, like the kind you use for household chores. This stuff’s way more nasty than B&W chemicals are.
  • Containers to mix and store your chemicals and something to mix them with.

Comments on the process

  • Gratification. Unspooling a roll of colour positives from your developing reel when the process is done provides way more instant gratification than the end of the B&W process does. You can see your final results, right there, right then.
  • Cost. The math works out to $15 to $20 for a small kit / 6 rolls per kit = $2.50 to $3.30 per roll. (American dollars here.) If you mount them yourself, count on about $2 for enough mounts to do the whole roll — or take them somewhere to get mounted. Total: $4.50 to $5.20 per roll. This is assuming you didn’t have to buy much new equipment. Sometimes I mount the slides myself, and sometimes I take them to a pro lab to be mounted. Of course, you don’t have to mount them — you can sleeve them, like negatives. This would be appropriate if you’re just going to use a film scanner on them and not project them. The cost including mounting works out to about the same as using Kodak or Fuji mailers. It then becomes a question of how anxious you are to see your results, versus how much free time you have to do the actual processing, versus your faith in the mail system… and so on.
  • Push processing. I charge myself absolutely nothing for push-processing. With pro labs, costs for push-processing can very quickly add up.
  • Control. Any mess-ups are my fault. (In addition, the individual solutions can be tailored to colour-match with particular batches of film, something that a pro lab wouldn’t want to be bothered to do. I suspect this is more of an advantage for heavy users, though, and is probably not so applicable to the three-bath system. Thanks to Gregory Blank for pointing this advantage out to me.)
  • Shelf-life. E6 chemicals have a short shelf life — much, much shorter than B&W chemicals do. I like to use up the entire 500 ml kit in one or two days. This makes for a lot of processing in one day and it gets tiring. You need to take this into account, and if you only have one or two rolls to do at once, it doesn’t pay to do them yourself. However, if you have a bunch of rolls to process at once, or can wait until you do, it’s worth it.
  • Time. The process itself takes about 40 minutes but mixing up the chemicals and getting the temperature right takes more time initially. The more times you do it, the more confident and faster you’ll get.
  • Automated processors. Companies like Jobo make automated processors that do a lot of the work (agitation and temperature control) for you. See my comments above. If you shoot a lot of film and live far from a good lab, these things can save you a lot of time and money in the long run. They take a lot of the physical effort out of doing E6 at home because they do all the agitation for you. However, they’re far from necessary for doing E6 and perfectly good results are achievable by hand.

Note added April 2008: There is a lot of discussion on the Net about 3-bath and 6-bath E6 kits. The E6 process formally has six chemical steps (hence the name); the 6-bath kits treat each step separately, which allows you to adjust times, temperatures, and pH levels of each step separately to correct shifts. All commercial labs run this “true” E6 process. The 3-bath kits combine some steps together to reduce the number of individual solutions, and the result is both a loss of chemical control over the individual steps and shortened working life. However, the storage requirements and kit sizes (1 L vs. 50 L) might make the simplied process more attractive for first-timers.

There are many comments on the Web that the 3-bath process produces inferior results to the true, 6-bath E6 process. After developing 12-15 rolls of slide film in the Tetenal 3-bath kit, I can say that this hasn’t been my experience. If you get a fresh kit and mix it as directed, using all solutions promptly and following Tetenal’s instructions, you will get good results.

Is processing slides at home really worthwhile?

In a word — yes, it’s worth trying at least once. Depending on where you get your slides done currently, it can mean a huge amount of cash saved over the long term. On the other hand, it can also get to be a major pain. In late June 2002 I processed six rolls of Fuji MS100/1000 (purchased out-of-date from Freestyle in Los Angeles and bulk rolled) in one evening — three cycles of two rolls each using the Tetenal kit, one after another, following the included instructions exactly. I started at 8 p.m. and didn’t finish up until almost 1 a.m. I was hot and sweaty (from all the agitating, pouring, etc.) and the bathroom smelled like bleach-fix. My fiancĂ©e was ticked at me for tying up the bathroom for so long (“just hold on until this last wash is finished”). I was so exhausted that I vowed to place an order for a bunch of A&I mailers the next day. On the other hand, seeing the six rolls of bright, colourful transparencies hanging in the kitchen was magical. So it’s a toss-up sometimes. If you have lots of money and not much time, or if you’re taking pictures for money, a pro lab is probably the way to go. But if you are a poor student subsisting on cat food … um, well, then you should try doing your own E6, or reconsider your priorities!

Last updated December 2nd 2002