second run with Tetenal/Jobo C-41 kit

[TheFlyingCamera]

Ok- I brewed up a batch of the 1L Jobo C-41 chems and ran a set of 6 rolls of 120 through it a week ago. I have two more rolls to run now. The stated capacity of the 1L kit is 8 rolls of 120. The working stock has been stored in Jobo bottles with the lids screwed on tight, in a relatively cold environment (my basement). I expect there will be some change in performance from fresh, but will it be bad enough that I should just toss this batch and brew up a new lot, or will I be fine?

 

[Rudeofus]

A number of folks have (there was a url link here which no longer exists) good results with overused and overstored C-41 process chemistry. Watch out for the following signs of deterioration:

1. Color developer will rise in pH and therefore activity over time. There will be fog (visible on the orange mask) if this becomes excessive.
2. Ferric EDTA oxidizes Thiosulfate, and Thiosulfate reduces Ferric EDTA. As a result your BLIX will become weaker in action, which will eventually leave silver on your film. This is not visible as fog on the orange mask, because undeveloped areas have no silver! Instead it shows up as weird colors, higher contrast and grain, and as low saturation.

 

[heterolysis]

I have done at least 12 rolls through 1L of C-41 chemistry before. I usually add 5-10 seconds for every roll I run through past the stated capacity when working with smaller kits. In my experiences, well stored chemicals should be good for a month or so before you have to worry about their potency. My films were coming out blue (when scanned) when my chemicals got old, and I could add time to the developer to compensate for it.

 

[Sirius Glass]

I too do 12 rolls on a batch on 1 liter C-41 chemistry. One of the people at FreeStyle told me that you can do up to 16 rolls, but I have not done that.

 

[adelorenzo]

Are you assuming that the Jobo and Tetanal kits are the same? Reason I ask is the instructions that come with the Tetenal 1L kits allow for a lot more than 8 rolls to be processed, they include instructions for extending the developing and blix times as you go.

I can't speak to the Jobo kit but I run 16-24 rolls through my Tetenal kits without issue and this is over a period of months.

 

[wjlapier]

Just curious. I too have the Jobo kit and will start my first batch of color development. Done plenty of B&W.

Do you pour the chems back into their storage bottles?

I have about 6 rolls to develop, but would like to run them one at a time to see what's happening before I feel comfortable.

 

[Rudeofus]

Do you pour the chems back into their storage bottles?

You can do that if these bottles have a wide mouth or you have a set of funnels. It is important for process uniformity that you pour liquids quickly. If that's not possible with your bottles, use a beaker or jug as intermediary container.

I have about 6 rolls to develop, but would like to run them one at a time to see what's happening before I feel comfortable.

That's a sound strategy, especially in a phase where you build up confidence in the process. What I usually do is develop one roll first, then when I see it comes out fine I process two rolls in parallel. Typical kit instructions are geared for more rolls per process run, so you have to interpolate a bit to get correct process times. With bleach, fixer and BLIX it's always good to err on the higher side, but color developer times may need some experimentation. Don't worry much, you can expect good results even if your CD times are a bit off.