I tried to get Bill Troop to explain the advantage of an alkaline fix vs. Rapid Fix, which has a very near neutral pH in a thread at photo.net this summer. He never did address that issue directly.
Originally Posted by Frank F
I don't think that Rapid Fix is going to cause you any problems when used with staining developers. And if someone knows of some resources that actually have done some testing to demonstrate there is an issue, I would certainly like to see them.
I've been using Kodak Rapid Fix without the hardener with Pyrocat with no blatantly obvious problems.
I intend to switch to an alkaline fixer as soon as my Kodak stuff is gone, but I'm too cheap to not use it up first...
To get some real data out there, I asked NACCO the Ph of their NuFix...
The PH of our Nufix is 5.32 (+ or - .01%). All of our fixers contain some acid.
We have a Odorless fixer that contains some acid but it does not have that acid
We also have Naccofix which is a ready to use fixer which contains a small
amount of acid and our powder fixer which contains less than 1% boric acid.