C-41 SHELF LIFE/CHEMICAL SENSITIVITY

Hello,

I've always been under the imperession that if I stored my C-41 developer in an oxygen-deprived, cool and dark environment that I really wouldn't have to worry significantly about the chemistry's shelf life. I only mix the C-41 chemistry I'll need for about 2 weeks, but perhaps I've been misinformed / under researched. Would someone be able to weigh in on the oxygen and temperature factors, say with respect to the Flexicolor developer that I use? I'd just as soon mix larger quantities and store them, but if they'll go bad I won't engage in that practice.

Thanks,

Junior

Question qualification

I just wanted to add that I've read many postings on oxygen and temperature sensitivity but could find relatively little agreement. Please forgive me if I've replicated a question that has already been answered (I'm really new), and point me to where I can find the anwswers.

I've found that color developer chemistry that is mixed and in a container with the air squeezed out can be useful for up to 6 to 8 weeks.

Take care of dissolved oxygen too

I concur with Snapshot - I mix C-41 from scratch, and have had success keeping it 6-8 weeks when cool (in the fridge in the summertime), and kept in full glass bottles. I have also had good results (not critically analyesed though, or tried on critical films) with murky dark stuff that has been used fresh, and then kept for a while, before using agian.

I typically develop about 8-9 rolls per liter, without any replenishment. One shot would be more precise, but I can deal with the slight variations in negative density that this proceedure gives me when I print them.

One of the keys I find for long developer life is to start with distilled or reverse osmosis filtered water that has been pre-boiled the left to cool to drive off the dissolved gasses before using it to mix the chemistry.

I use R/O water, since I have such a unit for tasty drinking water. I put a bit more than a gallon in a large stainelss steel pot on the stove, put the lid on, and bring it to a good rolling boil for a few minutes. Them without removing the lid I turn the heat off, and leave it to cool overnight. The next morning I will pour it into a glass gallon jug, and cap the jug. This is kept as a 'stock' to mix developers with. I don't go so far as to nitrogen blanket the water alone once the gallon jug of water is half empty.

Thanks Snapshot and Mike. Mike, I never even considered dissolved oxygen. Thanks for that suggestion. Sounds like I could get rid of the majority of it with little effort. I'm going to mix up a larger batch of developer. I only process 4 or 5 24-exposure rolls a week using developer on a one-shot basis (a friend suggested that as a newbie the one-shot deal would help me with my overall technique), so I've been mixing half batches, but I'd really love to try a whole batch. That would save me a lot of time as well as introducing another degree of consistency in my processing. I'd only be keeping it for about 4 weeks that way, but that 4 week figure always seemed to be out at the edge of developer viability when I tried to evaluate the conservative *and* liberal estimates as an average.

Also, I use a cartridge filter on my home water line. Do I need to start purchasing distilled water or using one of the R/O units Mike describes?

It depends...,

I go R/O becuase I am lazy, in a way - I used to do distilled water, but luggiing home jugs from the grocery store/ drug store in the winter was a hassle - always seem to get diverted with kids to the library, swimming lessons, etc. etc. , and then, will they freeze on way home, slip lugging it in from the car, etc.

The R/O unit I actually found on the roadside in an offical local annual trash picking week event. I fed it new filters ($140 every three years, otherwise about $15 every year), and spent about $40 in plumbing bits to hook it up. Otherwise it would still be distilled, becuase the thing if new would be over $500.

The fliter you have might be ok. It depends on where you live. Whatever is dissolved in the water is another variable to deal with.


Some places have a lot of dissolved irion wihich is a big no no with developers - the Fe wants the oxidizing action of the developing agent more than the silver that we want it to be solely devoted to. Only the developers are usually sensitive - if it is good tasting to drink, then it is no issue in using it in stop baths, fixers, bleaches, blixes, wash aids, etc. Distilled or R/O is good as a final rinse with a sparse amount of of photo flo wetting agent prior to drying films though.

Water testing

The water I have really is good tasting. I've drunk from wells and pumps and know well the taste of heavy Fe concentrations (actually when I hike or bike in forest preserves, I enjoy the taste of the Fe laden water when I can get it from a pump), but I can't say that my palate is sensitive enough for a genuine chemical analysis. I no longer have access to a proper chem lab. Can anyone recommend a decent commercially available kit for testing my water for mineral content?