A product for keeping chemicals fresh?

greenspun.com : LUSENET : Large format photography : One Thread

I have come across a product in a well know woodworking and tool store in Toronto (Lee Valley Tools) that could prove useful in the darkroom. It is an aerosol can containing a blend of nitrogen, argon and carbon dioxide - two of which gases are heavier than air. It is sold as a finish preserver - you shoot a quick blast into, say, an opened shellac container and then quickly cap the container. The gases displace the oxygen with inert gases and prevent oxidation. Apparently it is based on (or is the same as) sprays used to keep wine fresh in opened bottles.

So why could it not be used to slow down oxidation of developers and fixers? Is anyone out there already using something like it? It would certainly be more convenient than decanting liquids into smaller containers or adding marbles to eliminate air space.

Cost wise, the price is $13 CDN which is about $8.66US and the description says it will seal about 37 gallon sized containers or 75 quart sized containers and will provide over 150 seconds of discharge.

The answer to chemical longevity?

-- Alan Shapiro (ashapiro@yorku.ca), January 11, 2001


Could there be a possibility that the gas could chemically react with the liquid and cause problems??? I try to keep processing as constant as possible and this would be adding another variable, would it not???

-- Dave Richhart (pritprat@erinet.com), January 12, 2001.

Several companies market such a product. The one that pops into my mind is Tetenal - don't remember the name of the product though. A search under Tetenal or Jobo will pull it up.

-- Wayne DeWitt (wdewitt@snip.net), January 12, 2001.

The Jobo product is Protectan, I think. You could also use nitrogen from your nitrogen burst tank (if thats your choice of agitation). Carbon di oxide might be the one thing I would be a little leery of since it can combine with water to form carbonic acid, which can affect the pH of the developer, but these are probably baroque worries. Good luck. DJ

-- N Dhananjay (ndhanu@umich.edu), January 12, 2001.

This stuff has been around for years. It only works as well as the seal on the bottle. (There's a phenomenon called 'osmosis', remember?) Squeezing a plastic bottle until the liquid is up to the brim works better, and costs nothing.

-- Pete Andrews (p.l.andrews@bham.ac.uk), January 12, 2001.

I agree with Pete on this one... A cheap way to do this would be to get a bag of GLASS marbles to put in the bottle to bring the level up to cut down on the size of the chemical in the mouth of the bottle, well I hope you know what I'm saying... Cheers

-- Scott Walton (scotlynn@shore.net), January 12, 2001.

Moderation questions? read the FAQ