Inversion vs. Rotation for C-41 developing

Jessestr · Sep 17, 2014

Hi all

I used a jobo last weekend and after some troubleshooting all went great. Too bad it wasn't my jobo though and I'd love to process C-41 at home too.
As you can't find jobo's here so easily. I want to start developing C-41 with the inversion/agitation method. Will be using a bath that is controlled to 38°C.

Is there much difference on rotation or inversion? And is it even possible?

Thanks

heterolysis · Sep 17, 2014

I process my own C-41 in a standard Patterson tank with inversion all of the time. Never any issues. Just don't forget to put it back in the bath when you're done.

pentaxuser · Sep 17, 2014

The key here, I would think, is to have a trial run. Just use water in the tank minus a film and see if the water bath can maintain 38C in the tank liquid over 3 mins 15 secs. If not adjust water bath temperature accordingly. It is probably even more important that the film has a pre-wet at 38C before inversion processing than in a Jobo processor to get it to the right temperature to begin.

pentaxuser

Jessestr · Sep 17, 2014

Ok thanks! just another important question.

When rotating I need only 250ml to develop 2 rolls.
For agitating I need 500ml for 2 rolls.

Let's say 250ml only gives you 2 rolls until it's worn out (just an example). If I mix 500ml for two rolls (because I'm not rotating but agitating)... can I do 4 rolls with 500ml or only 2 ?

mablo · Sep 18, 2014

Jessestr said:
Ok thanks! just another important question.

When rotating I need only 250ml to develop 2 rolls.
For agitating I need 500ml for 2 rolls.

Let's say 250ml only gives you 2 rolls until it's worn out (just an example). If I mix 500ml for two rolls (because I'm not rotating but agitating)... can I do 4 rolls with 500ml or only 2 ?

Following your example you can do 4 rolls. In real life a 500ml batch of fresh C41 liquids will develop ten or twelve 35mm rolls before the chemicals get too weak. You just need to prolong the time for developer and fix (or blix). I add 15 seconds of dev time after each four developed rolls and at the same time add one minute for fix (blix)

polyglot · Sep 18, 2014

C41 is calibrated for constant agitation; you can use inversion but you're going to get tired!

kb3lms · Sep 18, 2014

You need to constantly agitate C-41 or you will get problems with color crossover. Remember, it is designed for machine processing which is always moving the film and chemicals.

Color crossover occurs when color layers don't process at the same rate. When that happens the response curve of the layers differ and you get weird color imbalances.

Keep everything moving while processing and you should be fine.

Mark Crabtree · Sep 18, 2014

All good advice. I usually prefer stainless steel tanks and reels, but this may be a situation where one of the tanks that let you rotate the reels would be an advantage.

I don't think you will need to worry about the constant agitation except in the developer step. 30 sec interval will probably be fine on the others, plus temp control is not critical after the developer. It is still time/temp, so you need to keep the temp up, but to the tolerance of the developer step.

pentaxuser · Sep 18, 2014

mablo said:
Following your example you can do 4 rolls. In real life a 500ml batch of fresh C41 liquids will develop ten or twelve 35mm rolls before the chemicals get too weak. You just need to prolong the time for developer and fix (or blix). I add 15 seconds of dev time after each four developed rolls and at the same time add one minute for fix (blix)

Does this need to be qualified by stating over what sort of time period that the C41 liquids will remain fresh for 10-12 rolls? I'd hate the OP to assume that he can do 10-12 rolls over say 6 months if the period has to be confined to 6 days/ 3 weeks etc.

I have no idea over what period Digibase kits, once made up to working strength developer will remain effective.

pentaxuser

fotch · Sep 18, 2014

The use to sell tanks and motor drives that will roll the tank. You may be able to find used for an affordable price. I think you can develop at lower temp by adjusting the time. Maybe not ideal but worth looking into.

RPC · Sep 18, 2014

When developing C-41 in small tanks and using inversion you do not use continuous agitation. See Kodak publication CIS-211.

Photo Engineer · Sep 18, 2014

At KRL we did not use constant agitation. We used nitrogen burst which is intermittent. It is about as non-constant as you can imagine. So, you can say that C41 is designed for both as long as you do it right. Basically, intermittent must be strong and vigorous.

The problems that people see are often due to the drop in temperature while hand agitating and that is a hard one to get around.

PE

PtJudeRI · Sep 18, 2014

Just keep a water bath to keep your tank in between agitations. Developed many rolls, no ill effects.

polyglot · Sep 18, 2014

In terms of keeping, C41 developer keeps really well in a completely full PETE bottle, especially if refrgerated. Concentrates will keep for a year or so under butane. I have personally tested the Fuji developers against identical exposures on two rolls and found no change in working solution behaviour after 3mo. I also buy the 1L bottles of Rollei concentrates (200 rolls' worth), keep the partial bottles under butane and they go fine for at least 18 months that way with no visible degradation of the results. If there is any air in the bottles though, the developer will die.

If you bought a smaller kit (say 1L/20 rolls) and planned to use it over 6 or 12 months, that would work fine as long as you stored it properly. A blix kit may not survive that long though; you want separate bleach and fix.

Athiril · Sep 19, 2014

Agitation by inversion every 15s or every 30s works well. I do 15s. 2 inversions.

I use a warm pre-wash, about 44 degrees celsius when it goes in - this will drop in temperature several degrees, if you don't warm up the tank and the internals of the tank, you'll find that your 38 degree C-41 developer will drop several degrees when you put it in. I use a weakly diluted acetic acid based stop after the developer. Then rinse quickly and head into the rest of the process. Bleach lasts longer this way.

Don't just rinse with water after C-41 developer. When I first started, rinse was fine, when I moved houses to a completely different area, I narrowed very high dMin (you dont want this) to rinsing after developer with the local tap water.

Even use an acidic stop or put it straight into bleach or blix after developer.

madgardener · Sep 19, 2014

polyglot said:
In terms of keeping, C41 developer keeps really well in a completely full PETE bottle, especially if refrgerated. Concentrates will keep for a year or so under butane. I have personally tested the Fuji developers against identical exposures on two rolls and found no change in working solution behaviour after 3mo. I also buy the 1L bottles of Rollei concentrates (200 rolls' worth), keep the partial bottles under butane and they go fine for at least 18 months that way with no visible degradation of the results. If there is any air in the bottles though, the developer will die.

If you bought a smaller kit (say 1L/20 rolls) and planned to use it over 6 or 12 months, that would work fine as long as you stored it properly. A blix kit may not survive that long though; you want separate bleach and fix.

Where do you buy the kits with separate bleach and fix? The only Rollei kits I have seen recently now use Blix.

polyglot · Sep 20, 2014

madgardener said:
Where do you buy the kits with separate bleach and fix? The only Rollei kits I have seen recently now use Blix.

macodirect.de. I've only seen digibase kits with separate bleach/fix.

Inversion vs. Rotation for C-41 developing

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