Managing C-41 chemicals and throughput

hoffy · Mar 29, 2012

I have in my hands a 1 litre Tetenal Colotec C-41 kit and 7 rolls of film to process through with my Jobo and I have a few quick questions:

How do people manage the use of the chemicals? I.E., do you just make 1 litre of stock solution, take from this, process and then return the solution back to the stock bottle to be used again, or do people discard a small amount after each process, which is then topped up with fresh chems (which would mean maintaining two bottles for each solution).
The tank on the Jobo has a suggested capacity of 270ml to 570ml. Typically, how much should I be using for processing 2 120 rolls on 1 reel?
The literature for the Tetenal kits suggests 16 rolls of up to ISO200 and 12 (I think, or is it 8?) rolls up to ISO400, based on a throughput of 4 rolls per process (I will be doing 2 rolls per process) what are peoples real world experience with throughput? (typically I err well and truly on the side of caution, but with this stuff, I would like to get as much as practical out of a kit)

Cheers!

hoffy · Mar 30, 2012

I knew that I should have put Kodachrome in the title

Anyone have any advice?

Cheers

hoffy · Apr 2, 2012

OK, I'll make it up as I go along!

I'm assuming that I can re-use the stock solution, as long as I extend the processing time for each 2 roll process?

Mr Student · Apr 2, 2012

When I used a Tetenal kit I heated the entire litre, even though I was only using 600ml or so with the Patterson tank I was using. All I did was adjust the development time with the recommendation in the manual that came with the kit. I found the kit to be pretty bullet proof, so don't stress about it and give it a go!

langedp · Apr 2, 2012

hoffy said:
OK, I'll make it up as I go along!

I'm assuming that I can re-use the stock solution, as long as I extend the processing time for each 2 roll process?

What do the instructions say that come with the kit? I use Kodak's Flexicolor C-41 chemistry so I have no direct knowledge of the Tetenal process. Typically for rotary processing the recommendation is to use the chemistry "one shot" and not replenish.

12-16 rolls in one liter of chemistry is a lot for C-41 unless you're running a replenished system and not "one shot" processing. 1 roll = 135-36 or 120 or 8x10. I can't get anywhere near 12 8x10's in a liter of Flexicolor.

hoffy · Apr 15, 2012

OK, so I have just finished my 9th roll in the 1 litre kit. As I have no more colour (& it takes me around 2 to 3 months to stockpile that much), I have called it quits with that kit. Its hard to say whether I have been successful or not, as the proof will be in the printing. The negs did look OK at a glance.

The pack says that its good for 4 runs (I did 5 - I won't dob if you don't) and you can get up to 16 rolls, based on 4 rolls at a time. If I were to run using half the kit & 2 rolls at a time for 4 runs, would I be asking for trouble or would this be OK? Is it the processing that is the problem or the cross contamination of chems that is the problem (I.E., dev into fixer)

Cheers

Mick Fagan · Apr 15, 2012

I haven't done C41 for a few of years, however I always used a 2% stop bath after the developer.

With Flexicolor chemicals, or ones that I put together from scratch, I always used 8 rolls per litre maximum, which from memory is about what Kodak says to do.

By using a stop bath you are ensuring that development is stopped exactly at 3'15", which is relatively important for consistency with C41, plus it ensures your next bath will last longer as there will be no carry over. C41 has the shortest developer stage of any normal film process that I know of, so ensuring development stops at the correct time is reasonably critical for the C41 process.

There are many variables, but if it works at the moment, keep on doing it the same, you should be right.

Mick.

hoffy · Apr 15, 2012

Cheers Mick. Been a while since I have seen you around here!

Athiril · Apr 17, 2012

It's 4 rolls of 35mm/36exp or 120 per litre before increasing the time, few more, increase the time again.

I replenish my stock solution with replenisher. But I'm not using tetenal chemistry.

Managing C-41 chemicals and throughput

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