Salt water to wash film?

[Captain_joe6]

I remember reading somewhere that hypo clearing agent was developed after navy photographers noticed that film washed faster in sea water than in fresh water, brought about by the limited fresh water available on ships. Does anybody happen to know if salt water is a viable alternative to HCA, or is HCA way, way better? Does anybody know the answers when its paper being washed instead of film?

[phfitz]

That was the story behind Perma-Wash, but it had to do with sea water in the middle of the ocean. Closer to shore it would be dirtier, doubt it would work well.

just a thought.

[Captain_joe6]

I thought the idea was based on the exchange fo ions. And in my mind, salt is very, well, ionic. Would it be possible to mix myself some saltwater to average oceanic salinity and use that?

[Sparky]

I don't see why not. I doubt the 'shore water' is ANY different as any other salt water is concerned. But if you want the real deal... order some 'instant ocean' which is a commercially available salt of very high quality including all trace elements (chrome, vanadium, gold, etc..) in their normal concentrations. However - I'm wondering if ordering an equivalent quantity of permawash wouldn't be about the same price. You'd have to check it out.

[Tom Hoskinson]

I thought the idea was based on the exchange fo ions. And in my mind, salt is very, well, ionic. Would it be possible to mix myself some saltwater to average oceanic salinity and use that?

A good Hypo Clearing Agent can be made by Mixing 20 grams of Sodium Sulfite in 1 liter of distilled water. As an option, !.5 to 2.0 grams of Sodium Bisulfite can be added as a pH buffer. Soak the film (or paper) in this HCA solution for 1 minute with continuous agitation, then drain and wash.

Sodium Sulfite and Sodium Bisulfite are available inexpensively on the Internet at: The Chemistry Store.

[Captain_joe6]

Cool, thanks all! When you're just a poor student working minimum wage and watching in horror as the gas prices continue to skyrocket, a gallon packet of Kodak HCA becomes far more expensive than a container of salt. I manage, though.

[Roger Hicks]

A normal wash aid is a 2% sodium sulphite solution in tap water, with up to 0.2% EDTA in hard water areas (0.5% to 1% is all that you need unless the water is VERY hard). That's 20 g/l and 0.5 to 2 g/l.

Strictly, this is a wash aid, not a hypo clearing agent, and there is no need to use either with film or RC paper.

Cheers,

R.

[Captain_joe6]

I thought that the unnecessary one was Hypo Eliminator? If Hypo Clearing Agent isn't needed, and it replaces (most of) the thiosulfate ions with sulfite ions, the latter being easier to remove, then what does a 'wash aid' do?

[Photo Engineer]

This is a very very old topic. A search of APUG and Photo Net will reveal many identical answers and some new ones.

PE

[Michel Hardy-Vallée]

For the difference between (Wash Aid / Hypo Clearing Agent) and Hypo Eliminators:

http://www.apug.org/forums/forum37/3...hypoclear.html

A wash aid IS a hypo clearing agent; it's just a different word for it. An eliminator is something altogether differently.