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Contamination Basics

toejam

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I'm decently new to developing my own film. I've been developing with C41 chemicals as well as Ilford's black and white chemistry. Currently I use different beakers and funnels for everything. I understand that's the best way to prevent contamination but is it a must?
 
Avoid contamination like the plague. It could cause unseen failures & you might never know where it all went down the chute. Like any other thing one does with passion do it like advised.
 
No. Assuming you do a reasonable job of keeping things clean.

Keeping dedicated storage bottles is a good idea, along with dedicated trays. But funnels and beakers aren't in contact with the chemicals for long enough to make any difference.

Black and white chemistry is very forgiving and getting a bit of fix in the developer won't do much of anything. Some processing schemes even have a bit of fixer in the developer formula. Of course, getting developer in the stop bath, and stop bath in the fixer, is part of the process.

Pouring developer into tray that has been used for fixer for many years can suddenly show a dark stain as silver that has embedded itself in the plastic gets developed. Color developer can form a tar on a photographic tray. Amidol and Glycin developers can stain plastics. Plain-ole MQ evelopers will slowly stain Nalgene, but it takes decades.
 
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I've never had multiple sets of graduates, funnels, and beakers. Never had a problem I couldn't easily trace to camera, film, or my own error.

Now bottles, I don't interchange -- in fact, these days, I buy them fresh for under a dollar, at the grocery store (I have to discard the club soda that comes in them, though). PET with a good cap seal is one of the best materials, and much cheaper than glass. Since my chemicals are stored inside a cabinet in my (dark, when I'm not in there) darkroom, I don't worry about protection from light; clear PET is fine.
 


Thanks Nicholas. This helps with my nerves. Also helps me not have to keep up with so many items. If I start processing slide film with individual beakers and funnels I'd go crazy.
 

Are you storing your black and white chemistry that way or your C-41 chemicals? Right now I have black accordion bottles for C-41 stuff and my b&w fixer.
 
I use glass graduates, beakers, and funnels, no need to separate set for developer, fix or stop, glass will wash up without problems. When I started in the 60s I used brown glass jugs for stock chem, again easy to clean. Over the years I have gotten rid of the glass for plastic bottles, made for photo chemicals. I do use one of bottles for developer, fix, and stop, will use the film developer for different developers, such as D76 or MCM 100. I have a complete separate set for C41, use quart size.
 
toejam said:
Are you storing your black and white chemistry that way or your C-41 chemicals? Right now I have black accordion bottles for C-41 stuff and my b&w fixer.
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Both. Accordion bottles are very expensive for what properly should be single use (when the contents are used up, they're impossible to clean, and they're not impermeable enough for the compression to matter). I have 2L bottles that came with store brand cola inside, and 1L from club soda.
 
I use dedicated PET bottles for C41 and RA4 chems. B&W developer I use one shot HC110 clone, I use gallon black plastic jugs from Freestyle for fix and stop. I always use the funnels and graduates in sequence (Dev, stop, fix) and rinse well when done, never had contamination problems. The accordion bottle material is permeable to air, not good and as Donald pointed out you can’t really get them clean.
 

Similar here for my B&W stuff. I store my chemicals in soda bottles and squeeze the air out before I close the lid. I wash them with dishwasher detergent followed by a thorough rinse with clean water and use them for the same type of chemical again.
After a couple of times of cleaning and usage I replace them.

The only thing I cannot get cleaned out with dishwasher detergent, is the black residue from storing used paper developer. I tend to use my developer for two evening sessions when they're not too far apart, and that residue doesn't come off the bottle by washing. It does come off easily with a paper towel, so that's what I use for them before I wash them.
 
The beauty of PET beverage bottles is that they're almost free.

They do have limited life with C-41 Developer Replenisher, especially if you're squashing the bottle to reduce airspace -- but since I had one crack while doing that, I started blanketing with butane (as sold for lighter fuel) instead. But I can buy a lot of replacement PET bottles (and drink or discard the original contents) for the price of one accordion bottle, and they protect the contents better from everything but light (and a closed cabinet in a darkened room does that as well as I could ask).
 
Same here, my chemistry is stored dark in a box inside a cupboard.
Just started using butane as well on my concentrates, but I've done that too short to notice how well it works for me yet.
Eg. Still struggling a bit with the amount I need to release into the bottle. (I use one of those kitchen torches where I removed the Piezo element).
 
toejam said:
... Right now I have black accordion bottles for C-41 stuff and my b&w fixer.
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Lose the accordion bottles. They are worse than just about anything else. The problem is that they are more gas permeable than just about anything else used for darkroom chemical storage, so even when compressed, they allow lots of oxygen in to degrade your chemicals. HDPE (high-density polyethylene) or glass or PET bottles are all better. Use smaller bottles and work out of just one, keeping the others topped up for maximum chemistry life.

Learn to rinse your graduates, beakers and funnels well and then don't worry about contamination. I use dedicated trays and bottles when possible, but would not hesitate to use either for something else if they were well-cleaned beforehand.

Best,

Doremus
 
I use Costco dust-off to expel oxygen from bottles - last I checked it's butane or some other -ane. Whatever it is it isn't oxygen and it isn't air. It seems to be the cheapest stuff around, though if you are willing to chance propane you can get a 20lb refill for around $20 - and if the outdoor grill ever runs out you have a spare on hand.
 
Nicholas Lindan said:
Pouring developer into tray that has been used for fixer for many years can suddenly show a dark stain as silver that has embedded itself in the plastic gets developed.
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So that's what happened! That just happened to me this weekend. I tried scrubbing it off, some came off but it's still stained. It doesn't bother me but will using it for fix again clean it out? Maybe I should label my trays.
 
Keep your hands clean when developing film or prints by hand. Neglecting that was my worst contamination.
 
Absolutely agree!
 
Using the same graduates, funnels and mixing containers for most darkroom chemicals is usually not an issue, as long as they are rinsed thoroughly between uses.
I use dedicated trays and tongs for developer, stop, fixer, hypo-clear and toner, but rinse them thoroughly between sessions. I also use dedicated storage bottles.
As others have mentioned, keeping your hands and fingers clean is probably the most critical to avoiding cross-contamination. I rinse my hands frequently while processing prints and make sure they are bone-dry before touching any negatives or fresh sheets of paper.
 
Soda bottles are pretty high tech. Thinking about gas permeability, soda bottles have extremely low gas permeability otherwise the CO2 would get out etc.
No substitute for a full bottle. I use butane as well. I'm very careful, last thing someone would want is a charge of butane exploding in the top of a bottle of some stinky chemical.

I bought some Nalgene PP bottles, they work fine but forget longer than a month for oxygen sensitive stuff.
 
Nitrile gloves are much easier to clean and dry off then human skin, and therefore less likely to contribute to contamination then bare hands.
I'm currently experimenting with wine bags for chemical storage.
 
Years ago I started to notice problems with chemicals stored in different types of plastic bottles so I chucked most of the plastic in the darkroom. The accordion bottles were the first to go and they ended up on a film set darkroom where they would do no damage. For colour, both E6 and C41, glass beakers, graduates, funnels and bottles are all glass. I use a "J" tube used to clean wine bottles which blasts a stream of hot water into an inverted bottle or beaker to rinse them out. Everything is labelled so it is used for the same chemicals. I mix all chemistry with a magnetic mixer so the only thing other than the glassware that needs to be cleaned is the magnet. Following the same procedures every time greatly reduces and contamination problems. I use the nitrile gloves most of the time to ensure there is no contamination. If there is an air gap at the top of the bottle I will top it off with nitrogen or an inert gas like the wine makers use.
 
MattKing said:
I'm currently experimenting with wine bags for chemical storage.
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I've heard good things about those (wine, also, doesn't like air beyond a few hours, and wine drinkers run to the, um, discerning side); I bought two 5L boxes (each with five bladders) to try with my new C-41 replenisher and EcoPro (still waiting on the C-41 chemical, though). You can also buy easy-fill replacement bladders, with a screw cap to fill -- makes it MUCH easier to put new replenisher into the bag vs. running it dry and installing a new one.
 
My bags were bought new. The boxes that hold them once filled are a bit of a kludge though.
 
BAC1967 said:
So that's what happened! That just happened to me this weekend. I tried scrubbing it off, some came off but it's still stained. It doesn't bother me but will using it for fix again clean it out? Maybe I should label my trays.
Click to expand...

You can rehalogenate the silver stain on your tray with good old household chlorine bleach, then fix it with regular fixer and then rinse it away. Other stains require a bit of scrubbing; Bar Keepers Friend or CIF work for me.

Best,

Doremus
 
Never knew about magnetic mixers but I’m on board with that method. Also slowly moving to all glass. Grabbing a beaker here and there.

What tools do you need to put the invert glass in the bottle?
 
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