C41 in Communal Darkroom

clingfilm said:

Could you explain this again for me please? What do you mean when you say 'last 500cc'?

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Sounds like he's decanting 2500ml of solution into four 500ml liter bottles and the remainder into five 100ml liter bottles. 1cc = 1ml.

Clingfilm, I have not heard good things about the accordian bottles, e.g., cheap plastic, bad seals, don't stay compressed. I use canning jars. They are glass, fairly inexpensive, come in several different sizes, and have a tight seal. They may not be appropriate for your situation. Glass is of course breakable, so you may want to use a high quality plastic like PET. Definitely have different sizes, this makes it easier to keep them full.

The pH of C-41 developer, even when stored properly, seems to go up in storage, increasing contrast a little. If that is not desirable, then bringing the pH back down to typical levels, about 10.1, will return contrast to normal.

clingfilm said:

Are you saying that we would get 17 rolls of 35mm per 5L Hunt kit or per litre of 5L Hunt kit?

Does the X-Press kit last longer than the other C41s? They would be sitting either as a concentrate or powder and then I would break off the 1L quantities as we needed them.

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17 films per 5L kit. I'd not leave the concentrates sitting around for a long time after opening - I'll check the instructions tomorrow & see what they have to say.

Avoid the accordions like the plague, get brown glass or Jobo/ similar plastic bottles.

bvy said:

I approach "definitely" with caution. If the clip darkens, it tells you the developer is not dead -- i.e. it should produce something on the film. That doesn't mean it won't produce a thin negative or bad color rendition depending on other things (how it was mixed, stored, its age, previous use, etc.). The clip test is more useful to keep you from dropping film in developer that is completely dead for whatever reason.

Also, it will work with any color film, though I'm in the habit of using a clip from the film I'm about to develop.

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Ok, at least it's something. Like you said, if it develops you know you'll get 'something' at the end of development. Do you have any experience with testing via pH? Some others have suggested that but again it seems a bit too good to be true?

Lachlan Young said:

17 films per 5L kit.

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Damn, I was expecting way more - can't you get like 16 rolls out of other 1L kits?

RPC said:

The pH of C-41 developer, even when stored properly, seems to go up in storage, increasing contrast a little. If that is not desirable, then bringing the pH back down to typical levels, about 10.1, will return contrast to normal.

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Looks like we will be investing in some new bottles then. As far as plastic goes I've seen people saying that as long as it's PET of HDPE then you're good, so could I just use old Coke bottles or something?

For the pH, if you used this in conjunction with the film strip development test, could you be fairly sure your developer is fine? Like if the developer pH is in a good range and it produces a dense negative in ~5 mins you could develop with peace of mind?

clingfilm said:

Damn, I was expecting way more - can't you get like 16 rolls out of other 1L kits?

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I was going by using it single shot in 290ml Paterson tanks.

Anyway, went and checked the instructions - & then found that someone had posted them on APUG - (there was a url link here which no longer exists)

Depending on film speed, you can get 90-120ish films through the 5L kit. The above link also gives the life expectancy of the mixed solutions.

clingfilm said:

Ok, at least it's something. Like you said, if it develops you know you'll get 'something' at the end of development. Do you have any experience with testing via pH? Some others have suggested that but again it seems a bit too good to be true?

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I've not done anything with pH testing.

For storage, I have a supply of old Sobe drink bottles that I use and reuse. They're plastic but they have thick walls and don't really yield when you squeeze them (compared to, say, soft drink bottles). I've kept C-41 developer for a little over a year in these and it worked great. They were filled to capacity, sealed tight, and kept in the dark in my cool basement. They're also 600ml in capacity, perfect for one shot use (one roll of 120 or two of 35mm).

Unfortunately, Sobe changed their bottle a few years ago. It's now pretty flimsy. But find the right plastic bottle, and it should work fine.

clingfilm said:

For the pH, if you used this in conjunction with the film strip development test, could you be fairly sure your developer is fine? Like if the developer pH is in a good range and it produces a dense negative in ~5 mins you could develop with peace of mind?

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As I said earlier, if the developer color is not too dark then it should work fine. But the film test can be done to double check for activity, and the pH check to fine tune the contrast (a small deviation) or discover other problems (a large deviation). Anything is possible, and I can't guarantee anything. I am only certain if my own experiences. The best advice is to use control strips or create your own test negatives.

clingfilm said:

Could you explain this again for me please? What do you mean when you say 'last 500cc'?

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No Problem.

Let me explain. I always use a jobo processer for developing C41 film. Each 35mm film needs 150cc of developer on a 'use once and throw away' principal. I was finding if I bought a larger kit than a 1 litre size. I was getting towards the end when one or more of the individual chemicals was 'going off'
I have now tried buying a 2.5 litre kit and mixing all at one go and then decanting 2 litres of it into 500cc bottles. The remaining 500cc (last) I decant into 5 x 100cc bottles and use them as required. I don't find that one of the bottles will have only 50cc left after the 1st film has any detrimental effect on the keeping qualities of what's left and so far have not failed when developing the next film even after a week or so.

I could of course acquire a 50cc bottle and that wouls save any problems. I am now down to the remaining 1/2 litre of that kit which I premixed all at one time and it still works as it should.