hypo stock solution shelf life

chris77 · May 19, 2016

hello.
i have mixed kodak hypo clearing agent last summer and kept it in capped PET bottles at low room temperature.
do you think its ok to use or does it go bad?

Doremus Scudder · May 19, 2016

Kodak says 3 months for the stock... I'd toss it. Wash-aids are mostly sodium sulfite and do oxidize. If you end up wasting a lot, you might just want to mix your own. I mix just enough for a session: 1 Tbsp of sodium sulfite and a pinch of sodium bisulfite for a liter. If you have hard water or water with lots of dissolved minerals, you should mix this in distilled water or use a more complicated formula with chelating agents:

Water 500 ml
Sodium Sulfite (anhydrous) 20g
Sodium Bisulfite 0.25g
EDTA Terasodium Salt 1.25g
Sodium Citrate (5,5-hydrate) 1.25g
Water to make 1 liter 1 liter

I have good luck with the simple formula, one-shot.

Best,

Doremus

chris77 · May 19, 2016

Doremus Scudder said:
Kodak says 3 months for the stock... I'd toss it. Wash-aids are mostly sodium sulfite and do oxidize. If you end up wasting a lot, you might just want to mix your own. I mix just enough for a session: 1 Tbsp of sodium sulfite and a pinch of sodium bisulfite for a liter. If you have hard water or water with lots of dissolved minerals, you should mix this in distilled water or use a more complicated formula with chelating agents:

Water 500 ml
Sodium Sulfite (anhydrous) 20g
Sodium Bisulfite 0.25g
EDTA Terasodium Salt 1.25g
Sodium Citrate (5,5-hydrate) 1.25g
Water to make 1 liter 1 liter

I have good luck with the simple formula, one-shot.

Best,

Doremus

good info... thanks!

Gerald C Koch · May 19, 2016

Your title for this thread is a bit confusing. Hypo refers to fixer and not clearing baths. Kodak uses the term Hypo Clearing Agent HCA which is a common abbreviation on APUG.

I might also add that it is not a good idea to save partially used JCA. The used solution provides a friendly environment for mold growth and mold spores can be transferred to film and paper. SO use HCA as a one-shot.

BradS · May 19, 2016

Gerald C Koch said:
Your title for this thread is a bit confusing. Hypo refers to fixer and not clearing baths. Kodak uses the term Hypo Clearing Agent HCA which is a common abbreviation on APUG.

I might also add that it is not a good idea to save partially used JCA. The used solution provides a friendly environment for mold growth and mold spores can be transferred to film and paper. SO use HCA as a one-shot.

+1

The term "hypo" is an obsolete name for Fixer. Thus, Hypo Clearing Agent is a solution that clears the fixer. HCA is definitely NOT Hypo.

I can also attest to the veracity of Mr Koch's second bit of advice. Mold and mildew stuff loves to grow in HCA stock solution. Mix and use as needed. Best not to store it too long.

chris77 · May 19, 2016

well, sorry for confusion. i meant hca. and i meant unused stock solution kept in a cool and dark room for at least 8 months in full pet bottles with very little air. guess i will use it, as i have no time to wait with a project and no stores nearby. if it doesnt help - it won't harm... thanks

Gerald C Koch · May 19, 2016

Some people add a small amount of Listerine to their HCA stock. It has to be the old fashioned amber stuff that tastes really bad. The thymol in the Listerine inhibits bacteria and mold growth. Add about an ounce to the stock.

hypo stock solution shelf life

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