Shelf Life of Kodak HCA?

Sirius Glass · Nov 29, 2014

The shelf live of Kodak Hypo Clearing Agent is three months in stock solution. What is your experience?

L Gebhardt · Nov 29, 2014

I've never known how to test it, so I've trusted Kodak's numbers.

pentaxuser · Nov 29, 2014

I wonder what is in it to makes its life as short as that. I look forward to hearing from regular users and chemists

pentaxuser

tkamiya · Nov 29, 2014

If I have any air in the bottle, few days later the bottle (plastic) caves in. So I know it consumes air (oxygen?)

I used to use it for 6 months not knowing storage life is shorter per Kodak. Since I have no ways to test if HCA is still good, I do the same as I do to developers. Store them in a smaller container and use it fast.

I really wish if there is a way to test this.

Gerald C Koch · Nov 29, 2014

Solutions of sodium sulfite rapidly absorb oxygen from the air. This limits the life of such solutions. In addition I do not recommend saving the used working solution as it collects bits of emulsion and other matter and soon grows mold and bacteria.

RalphLambrecht · Nov 30, 2014

Sirius Glass said:
The shelf live of Kodak Hypo Clearing Agent is three months in stock solution. What is your experience?

That's a conservative estimate. I mix my own;It's so easy to do and you always have fresh sstockbut I would use Kodak HCA stock up[ to 6 months without hesitation.

RalphLambrecht · Nov 30, 2014

Gerald C Koch said:
Solutions of sodium sulfite rapidly absorb oxygen from the air. This limits the life of such solutions. In addition I do not recommend saving the used working solution as it collects bits of emulsion and other matter and soon grows mold and bacteria.

Ah yes, that's where the fowl smell comes from.my working solution smells like old socks within two weeks but an ounce of Listerine in the Stock solution seems to prevent that. always wondered about that, thanks for the info.:confused:

Gerald C Koch · Nov 30, 2014

RalphLambrecht said:
Ah yes, that's where the fowl smell comes from.my working solution smells like old socks within two weeks but an ounce of Listerine in the Stock solution seems to prevent that. always wondered about that, thanks for the info.:confused:

The Listerine seems to work quite well. But as you mention the stuff is so easy to make up that its easy to use fresh each time. I'm always worried about some particles sticking to the emulsion and never reuse HCA or substitutes and any stop bath. Then too if you save some solutions for reuse they're another jug cluttering the darkroom.

RalphLambrecht · Nov 30, 2014

Gerald C Koch said:
The Listerine seems to work quite well. But as you mention the stuff is so easy to make up that its easy to use fresh each time. I'm always worried about some particles sticking to the emulsion and never reuse HCA or substitutes and any stop bath. Then too if you save some solutions for reuse they're another jug cluttering the darkroom.

I agree with Gerald;mixing fresh at the start of each printing session is the best way to go

Shelf Life of Kodak HCA?

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