Does fixer test solution identify fixer that is too old in addition to fixer that is too used? I've got some fix that has been around longer than 2 months in a less-than-full bottle. However, while I know that the test solution will tell me if it has too much silver in it to be effective, I don't know if it will tell me if its too old (too much oxidation?).

Thanks

ben

-- ben (grosser@uiuc.edu), April 05, 2000

Answers

To find out if your fixer is still active take a piece of un-exposed film and put it in your fixer and see how long it takes to fix, then double the time, if it is over 6 or 7 minutes you might want to make fresh fixer. I have had fixer that was 8/9 months old still working in 5 minutes. Regards, Pat

-- pat j. krentz (krentz@cci-29palms.com), April 06, 2000.

The time given by Pat applies to plain hypo fixers (Sodium thiosulphate). I wouldn't want to keep using a rapid fixer that usually takes two minutes to fix a film when it takes three to clear one!

There is a safer method than this: Use test strips. They tell you how much silver there is in your fix. If there is too much (the upper limit is 8 g/l for films in ammonium thiosulphate based fixers), discard the fixer. For FB prints the limits are much stricter.

-- Thomas Wollstein (thomas_wollstein@web.de), April 06, 2000.

Fixer doesn't oxidise the way that developer does. A couple of months storage is nothing, even if the bottles aren't full. The only deterioration that fixer suffers with time is that if it's stored partly used it'll throw a sediment of silver or sulphides out of solution. Even then it's recoverable if the solution is filtered.

-- Pete Andrews (p.l.andrews@bham.ac.uk), April 07, 2000.