Thursday, January 20, 2011

Processing Your First Colour Negative Film

Its not as hard as you think!
In these days of ever shrinking film market we often find ourselves looking for a good photographic lab for colour work which can sometimes be hard. So if you can't find one why not have a go yourself? There are some excellent kits now available from Tetenal, Rollei and Fuji-Hunt.

 Quite a few of you will already be processing your own B&W so already own  most of the equipment needed.
Hold on I hear you say-isn't colour processing complicated?

Processing colour negative film is as easy as B&W in fact in a lot of ways it is easier. The equipment you need for C41 negative is exactly the same as B&W with the exception of the thermometer which will need to go up to 40°C.
As the development time is the same for all C41 films 3 mins and 15 seconds the only hard part is keeping the developer at the standard 37.8°C ± 0.2°C
My method for keeping the developer is to use a water bath which I heat with a cheap fish tank heater which keeps the solution at the required temperature.
I use a 1L C41 kit which has three baths, Developer, Bleach/fix and Stabiliser (final rinse)

Here is my method:
I place the developer bleach-fix and stabiliser in the plastic washtub which I then fill with warm water at about 35°-40°C (around 100°F) I then switch on the tropical fish tank heater which maintains the temperature.

Then load the tank as you normally would with B&W film.

The chemicals need time to come up to temperature and stabilise, so put your thermometer in the developer bottle and keep an eye on it, the C41 developer is rated at 37.8°C (100°F) but half a degree either side won't matter.
Once up to temp, fill a clean container with water at 38-39°C this water will be used for  pre-soaking the film, which will help to keep the developer up to temperature by warming the tank and ensure the developer goes evenly over the film.
I pre-soak for two mins and while I do this I get ready my timer ( a watch with second hand is fine) and a pen and paper to note the passing time.

Pour out the pre soak water (it will be a coloured liquid, which is normal) and slowly pour in your developer (should take 15 seconds) and start your timer and initial agitation of about 15 seconds-tap the tank to dislodge bubbles.

Important Note: It is easier to use the agitation stick with some models like the Patteson System 4 you can keep the thermometer in the tank by placing in the centre of thestick. If you use inversion method after the initial agitation the air inside expands so you'll need to crack off the lid to let the warm air out-or risk leaks!

Keep an eye on the time as agitation should be every 15 seconds either by 2 inversions or twists of the agitation stick. During this time I prepare another jug of water at 35°-39°C which I use as a non standard wash to prolong bleach life.
The developer time for fresh solution is 3 minutes 15 seconds, so after the 3 min time take off the lid and slowly pour your developer back into the holding bottle(a funnel can help here), then put in my previously prepared first wash (you can use acid stop bath) which should be at the same  temperature (within a degree or two) as your processing solutions.

Agitate the wash/stop for 15-30 seconds then empty. Next pour in your Bleach-fix which should be over 35°C (as close to you developer temperature as possible) and agitate for a full minute then tap.
Remember to release the air if you use the lid and inversion

Prepare another jug of wash water at least 35°C.
Further agitations at 30 second intervals until the 6 min bleaching time is completed (you can't really over bleach-fix.
When finished pour the bleach into its holding tank and pour in your warm wash water and agitate for 1 minute, pour out the wash then re-fill with another warm wash and repeat until you've done this step five times.
Next pour in your stabiliser-don't agitate! just leave for one minute before taking out your film and hanging to dry.
N.B The stabiliser is the final bath, no further washes or wetting agents should be used.

That's it you're done! I actually find it easier than B&W, give it a go practice on cheap film/test shots until you're confident, but colour is nothing to worry about.
Here is an image developed from a Tetenal kit:

Developer is the most critical step, keep the temperature as close to the target 38°C as you can. Developer times should be extended by 15 second after every 5 films, a 1L kit should do 12-15 films.
If you process a lot of 400-1600 films take the lower figure of 12 as they exhaust the developer faster-you kit should have more information.
 Quite a few of these kits say "for rotary processors' but can quite easily be used for normal tanks as long as agitation is given every 10-15 seconds (not all commercial processors have constant agitation)
Developer changes colour from honey-gold to pinkish brown this is normal, in well sealed bottles should last 4-6 weeks its main enemy is air.
Keep developer away from all other chemicals especially bleach if you contaminate the developer with bleach-discard it (follow your countries laws about disposal)
Bleach likes air just before use, in fact commercial labs pump air though the bleach to condition it- I shake my bottle before use to get air in the solution.
Extend the bleach time to 10mins after you've processed 10 films.
Stabiliser will go from clear to pink during use-this is normal.

©Photo Utopia 2011