So if I had the 10 roll kit it would just fill my 16 oz. tank and I would make 5 runs with 2 rolls each and use the same chemicals 5 times. Would this be correct for 10 rolls of 35mm.
Yes, I've reused C-41 chemicals for 5 times with no problems in Jobo. Of course, the more you reuse, the higher the chance that the process goes outside the specifications. There are a few things to consider:
- Developer exhaustion (oxidization when it develops the film). This is counteracted by time compensation, but it can never be 100% exact as it depends at least a bit on films used, scene content (densities) etc.
- Developer dilution, if you use prewash and don't drain well enough
- Cross-contaminations. Try to keep things clean, especially the developer.
- Solutions lost in the process. You lose at least 10-20 mL every time in Jobo, so you must have some extra volume to begin with.
- Bleach buffering capacity lost due to too much developer carry-in. Try to drain as much developer as possible from the tank when you are going to reuse.
- Too much bleach carry-over in fixer. You could extend the in-between wash if you are going to reuse.
These all apply to any C-41 chemistry from any manufacturer. I don't believe Rollei would make a big difference.
However, I find C-41 quite a robust process and even if you went a bit out of specs, it doesn't usually show up---the results look good. Many commercial labs (not real pro labs) may be more off all the time.
For those of you waiting for my test results, I have shot and processed all the rolls and printed them, however, I am repeating all of this to verify my findings before making conclusions. I'll post the short hand results here, but I intend to write a more thorough article about it as well. Right now I am waiting on delivery of a second batch of chemicals to arrive.
It will be interesting to read.
Originally Posted by Greg Davis
I'm considering buying a Digibase kit; does anybody know what the shelf life is for the chemicals once opened?
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If you can displace most of the air from the bottles, probably at least a year or more.
But, the part containing CD-4 may die in even less than 6 months if the bottle is big and cannot be squeezed. This is the case with Fuji Hunt 5 l kit. I have started storing the developer concentrate parts in a fridge, and it seems to extend the shelf life even if I cannot squeeze all the air off. This seems much easier than playing with inert gases.
Probably very long since the bottles of concentrate is not full or even sealed at delivery.
Originally Posted by kiebee
However, they probably had a inert gas injected into the bottle to displace oxygen. Of course, one could also do this after opening the bottles, should help it last longer.
Originally Posted by steelneck
Please, enlighten me. I am confused about the shelf life of Rollei digibase DEVELOPER. Maco website states:
The color developer, working solution, example 250ml: One can at least process 5 films in a approach of 250ml. This requires a rapid processing (within 6 hours) ahead. .."
So, working solution last only for few hours and after that it's ruined?
Maco's developing instructions say that "250ml = 3-5 rolls" and in the instructions there is mentioned only this normal non-rotation method (like B&W). I have to say that I have never seen a tank that can develop 120 roll with 250 ml.
So, I have to mix 500ml of developer = about 12 rolls and develop everything within few hours if I want to use normal non-rotating method?
Or is that mentioned developer sorking solution shelf life ("6 hours") BS?
PS: Sorry, I don't know all the right terms.
I can't help you with your main questions; however....
It's still not quite 250 ml, but check out this 120-format developing tank. I've got a couple of these and they use 260 ml of solution (the figure is stamped on the lid, and you can sort of make it out in the auction's photo); however, they can't use inversion agitation, just rotational agitation via a rotating stick. I find this very difficult to get right, so negatives developed this way often have streaks. If you're used to this type of agitation and want to save a little money on chemicals, one of these tanks might be just the thing. I believe that Jobo-style rotary tanks could also do a roll of 120 in a similar amount of solution, but I don't know the exact figures offhand. I've seen posts from people who use Paterson-style tanks in this way (rolling them on a countertop) to save chemicals, but I've never tried that.
Originally Posted by pmu