Making Fixer

rob91 · May 27, 2008

I bought a bag of Kodak Pro powder fixer, I was mixing it in the bottle at recommended temperature, and for the most part it dissolved but there are a few hard chunks of fixer that didn't dissolve. I tried breaking them up and while they crumbled they did not dissolve. Do you think it is still usable? Now that I think about it, the fact that there are some small, hard pieces in the solution is a problem because if it got in the tank they might scratch the film. Oh well.

I'm still baffled as to how this happened, my temperature was certainly correct. The 1 gallon jug was only about half full of water though, maybe that was it? I think I might just go with the liquid solution next time.

edit: Also, if I end up tossing this fixer (which I Imagine I will) is down the sink okay, or should I find a more "environmentally friendly" way?

christopher walrath · May 27, 2008

I honestldo not know but this is one reason an old photo prof once told me to buy liquids. They're easier. It might still be ok if you can get the chunks out. The strength might be slightly in question though, as long as the VAST majority was dissolved well, shouldn't be a HUGE problem.

Rhys · May 27, 2008

Put your fixer container into a bath of warmer water - around 30 degrees centigrade. Then stir the fixer and it will all dissolve. There will be no harm to your fixer. It doesn't oxidise unlike developer.

Helen B · May 27, 2008

As Rhys says, warm it up and stir. You can go even warmer than 30 °C if necessary. As hypo dissolves it cools the solution, so you can start out with water that is warm enough, and as the hypo dissolves the temperature will fall.

In future, if you use a water bath (not an acid stop bath) between the developer and the fixer you can use plain hypo one-shot, at about 20% concentration or less. When used this way no other chemicals are required to prevent changes to the fixer. Hypo is very cheap when brought from pool supply shops, and is simple to make up when needed.

Best,
Helen

rob91 · May 29, 2008

Helen, i don't know what you mean when you mention Hypo, unless it is the Hypo Clearing Agent.

Thanks Guys, I will try warming it up. Out of curiosity, for the future, the bag of fixer says to mix the powder with water at around 68-75 farenheit, would there be any harm in using hotter water so it dissolves better?

compur · May 29, 2008

rob91 said:
Helen, i don't know what you mean when you mention Hypo

Hypo = fixer.

Helen B · May 29, 2008

To be more specific, hypo is short for sodium hyposulphite, better known these days as sodium thiosulphate. It is the main ingredient in conventional fixers such as the one you are using. ('Rapid' fixers contain ammonium thiosulphate and/or, less commonly, sodium thiocyanate instead).

In the USA hypo is commonly available for the dechlorination of pool water, and it can be used as fixer on its own. Used on its own it would decompose if there was any carry-over of an acid stop bath into the fixer, hence the recommendation that if you use a plain hypo fixer you should use a water rinse instead of an acid stop.

Commercial fixer mixes, such as the Kodak one you are using, include other chemicals to preserve the thiosulphate in the presence of the acids commonly used in stop baths.

Hypo Clearing Agent is an agent that helps to get the intermediate thiosulphate-silver complexes out of the film or paper. You don't really need it for film.

Best,
Helen