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Anonymous
A couple of quick questions about developing film /p/:

I have some kodak concentrated liquid developer and it says to mix the entire bottle with water to make a "stock solution". Would it be better, in terms of how long the developer will last, to mix all of the concentrate at once or should I only mix half?

Also do those opaque accordian bottles (on Adorama they are called Air-Evacu) make that much difference in the life of your chemicals? I'm not going to be developing too often so getting the most out of my chemicals would be ideal.
>> ac !!VPzQAxYPAMA
I, too, would appreciate answers to these questions.
>> Anonymous
Would it be better, in terms of how long the developer will last, to mix all of the concentrate at once or should I only mix half?

The primary issue that limits the useful life of developer is oxidation, so the more you can limit exposure to air the longer it will last. I would imagine (though I've never tested it myself) that once the bottle has been opened and oxygen allowed inside, the lifespan of the concentrate is about the same as stock solution.

>>77475do those opaque accordian bottles (on Adorama they are called Air-Evacu) make that much difference in the life of your chemicals?

Yes, I've had D-76 stock solution last well over a year in vacuum bottles whereas it gets iffy after a couple of months in ordinary containers.
>> Anonymous
If you don't have access to those fancy accordion bottles then keeping solution in the thinnest container is the next best solution, right?

Less surface area exposed to air in the bottle -> slower oxidisation?
>> Teus !QbSstcPD6U
>>in terms of how long the developer will last
only dilute liquid developer when you actually need it. usually diluted liquid only lasts 24hrs. no idea for european concentrate of HC-110, I got the USA syrup myself. I just dilute before I use it, saves a lot of hassle

>>opaque accordian bottles make that much difference in the life of your chemicals?
theyre accordeon bottles so you can squeeze out the air. unfortunately, the bottle "breathes" a bit through the folds. for max performance, use dark glass bottles with a special gas on top of it (forgot its name), otherwise its just awwright to use accordeon bottles

>>Yes, I've had D-76 stock solution last well over a year in vacuum bottles whereas it gets iffy after a couple of months in ordinary containers.
yeah. if no air can get to it, it lasts longer. full sealed bottles can last a while.

enjoy HC-110, I love it.
>> Anonymous
the fluids come with technical info.
read them
>> Anonymous
The way to keep it "fresh" the longest would be as follows:

1) Don't mix it all at once. Mix only what you need. The chemicals will be exposed to oxygen during mixing, and also to the dissolved oxygen in the water. Concentrate lasts longer than mixed developer.

2) Keep the developer with as little headspace as possible (headspace is the air at the top of the bottle.) One way to reduce headspace is with an Accordion type bottle. Another is simply to use smaller and smaller bottles.

3) Use a glass bottle if you can. All plastic bottles are somewhat permeable to oxygen. Though they are "airtight" a small amount of oxygen can and will diffuse through the plastic over time. A glass container won't do that. Unfortunatley, you can't get a glass accordion bottle, so the best thing would be to use a glass bottle that is as small as possible, but still has enough volume to contain the remainder of the developer.

If you are really serious about this, keep it in a cold, dark, place. A mini refrigerator is great. Cold slows down chemical reactions, making the developer last longer. However, be safe: don't keep it in the same fridge as food.