One advantage of the E-6 process is that it is relatively easy to handle in the home darkroom. Indeed, you don't even need a darkroom to be able to process your own reversal films.
You can cut the cost per film by purchasing the larger 3.8 litre professional kit for a round £50. This kit will process up to about forty 36 exposure 35mm films. So you can see how this can bring the cost down considerably - to approximately £1.25 a film.
However, if you only need to process a few films a week you'll end up throwing the solutions away before they've reached the end of their useful life, and the cost per film goes up again.
Having said that, there are many less expensive small kits on the market, such as those made by Tetenal, Fotospeed, Paterson and Photocolor. All of these reduce the cost per film quite considerably - to about £2.15 in the case of the 500ml Tetenal UK-6 processing kit.
Lake in Northern Italy photographed by Derek on Ektachrome 64 and processed in home-made E6
Apart from economy, you get several other benefits from processing your own E-6 films. The first of these is speed. Even the most efficient professional lab will take at least a couple of hours to process your films. And unless it happens to be next door you have to add the time and inconvenience of taking and collecting your film. On the other hand, if you do the job yourself you can be examining the results within an hour of taking your pictures - if you have the chemicals mixed and up to temperature. This is, of course, a big advantage when you are shooting in the studio, because it means you can leave the lighting set up until you see the transparencies. It also enables you to shoot a test film to see if you need any slight filter adjustments on the camera to correct the colour balance before you shoot your final pictures.
Another benefit is that you have full control over your processing. You can, for example, up-rate or down-rate your films according to the shooting conditions and change the standard process to compensate. I know that most professional labs offer this service, but it often takes longer and they normally charge extra for it.
If you take care handling and processing your films the quality of your transparencies should be at least as good as those you get from a professional lab. Because you're doing the job yourself youÕll inevitably take more care than a lab that's set up to produce commercially acceptable results from thousands of films every day.
Finally, the great thing about processing your own reversal films is that you donÕt need a lot of equipment. Just a processing tank, an accurate thermometer and timer, a few measures and some means of keeping the temperature of the solutions constant.
For temperature control I simply use a bowl of water at a degree or so higher than the process temperature. I stand all the bottles of processing solution and the tank in it, and as the temperature of the water starts to drop I add a little more hot water to bring it back up again. Alternatively you could use a small aquarium heater and thermostat to keep the temperature of the water constant.
One final piece of equipment you'll need is a No 2 Photoflood bulb in a reflector. This is for the reversal exposure that comes part way through the process (some commercial E-6 kits do not require this). For each of the processing solutions, dissolve the chemicals in the order given in the formula. If you don't, you may find that some of the chemicals - such as the Phenidone in the first developer - will be difficult or even impossible to dissolve. Ordinary drinking water is perfectly adequate for mixing the solutions (you don't need distilled water) and the Calgon in the two developers overcomes the effects of hard water.
It is worth filtering the solutions into their storage bottles to remove particles of dust and other debris. Make sure each chemical is completely dissolved before adding the next and after you add the 0.1 per cent potassium iodide solution, rinse the measure out with some of the mixed developer.
Sodium hexametaphosphate (Calgon) 2.0 g Sodium sulphite, anhydrous 39.0 g Potassium carbonate, anhydrous 14.0 g Sodium bicarbonate 12.0 g Phenidone 0.6 g Hydroquinone 6.0 g Sodium bromide 2.2 g Sodium thiocyanate 1.0 g Sodium hydroxide 3.3 g Potassium iodide, 0.1 per cent solution 4.5 ml Water to 1.0 litre
Sodium acetate, anhydrous 30.0 g Acetic acid, glacial 6.0 ml Water to 1.0 litre
Sodium hexametaphosphate (Calgon) 2.0 g Trisodium phosphate crystals 36.0 g Sodium hydroxide 3.0 g Sodium sulphite, anhydrous 4.5 g Sodium bromide 0.65 g Potassium iodide 0.1 per cent solution 30 ml Sodium thiocyanate 1.3 g Citrazinic acid 1.25 g CD3 11.0 g Water to 1.0 litre
Potassium ferricyanide 80.0 g Potassium bromide 20.0 g Disodium phosphate, anhydrous 12.0 g Acetic acid, glacial 5.0 ml Water to 1.0 litre
Sodium thiosulphate, crystals 200.0 g (or anhydrous 125.0 g) Sodium sulphite, anhydrous 5.0 g Sodium metabisulphite 0.5 g Water to 1.0 litre
Formaldehyde, 40 per cent 5.0 ml Wetting agent 1.0 ml Water to 1.0 litre
Step Time Temp deg C 1st develop 6.25 min 38+/-0.3 Stop bath 1 2 min 33-39 Wash 2 min 33-39 Reversal exposure Š see note 1 2 mins each side to No 2 Photoflood at 10 inches Colour dev 6 min 38+/-1 Stop bath 2 2 min 33-39 Wash 2 min 33-39 Bleach 5 min 33-39 Rinse 0.5 min 33-39 Fix 5 min 33-39 Wash 6 min 33-39 Stabilise 1 min 33-39 Dry See note 6