For years, when printing, I used Edwal Hypo-Check to verify that the Kodak fixer in my tray is not exhausted. The drops of Hypo-Check turn milky if the fixer should be changed.

Now I am using different fixers, those from Ilford (Universal Fixer) and from Photographers Formulary (TF-4). They require a much shorter fixing time and I suspect they are substantially different, chemically, from Kodak Fixer.

My question is: can I expect my Edwal Hypo-Check to be as effective in testing the new fixers as it was with the Kodak? If not, what is a good substitute for checking fixer? Photographers Formulary sells such a product, but can I expect it to be effective with Ilford Universal as well?

-- Paul Arnold (osprey@bmt.net), December 01, 2000

Answers

For what it's worth: Photo Formulary told me their fixer test is good for all fixers, including TF-4, which is an alkaline fixer of substantially different chemistry than most.

I believe fixer check reacts with silver ion in solution in the fixer, producing a precipitate. Makes sense that it would work with different fixers. (However, makes sense and being true often diverge...)

-- Don Karon (dkaron@socal.rr.com), December 01, 2000.

Fixer checks tend to not work with rapid fixers. At least not by putting a drop into the tray.

-- Terry Carraway (TCarraway@compuserve.com), December 02, 2000.

Somewhere or other recently I read that Hypo-Check can detect only rather large amounts of silver, far higher than what would be considered suitable for any sort of archival standards.

-- John Hicks (jbh@magicnet.net), December 02, 2000.

BTW Porter's (www.porters.com) sell silver test strips. These are colorimetric test strips that indicate smaller amounts of silver than the fixer check.

-- Terry Carraway (TCarraway@compuserve.com), December 03, 2000.

I wouldn't trust Edwal Hypo-Check for single bath fixing. I think it's fine for two bath fixing, for which I've been using it for many years.

-- Tim Brown (brownt@ase.com), December 06, 2000.