Quote Originally Posted by pentaxuser View Post
I have read all the posts and I am somewhat confused about the advantagesof alkaline over acid, specifically in respect of staining developers. One post says no effect on staining with pyro while another says there is an effect. In the case of no effect it is clearly based on pyro and actual experience while I wasn't sure if the other poster was talking from experience of trying both alkaline and acid or was taking the use of alkaline as being better as perceived wisdom.

Closer to home i.e. the U.K. a popular staining developer is Prescysol which may or may not be similar to pyro in terms of the effect of acid fixer and the maker most certainly recommends an alkaline fixer. Has anyone done an experiment of trying a roll in Prescysol with acid then one with an alkaline fixer to see if there is an effect on stain. Clearly if there is an adverse effect on stain from acid fixer then not to use alkaline negates the benefit of using Prescysol in the first place and the case for an alkaline fixer is proven - at least in the case of Prescysol.

Just to clarify from a personal point of view I've only carried out a visual comparison with Peter Hogan's alkaline and Fotospeed's acid fixers with 4x5 T-max 100 developed in PMK pyro and I could not see a visual difference as to the amount of stain. They looked the same to me.

While I have used Peter's excellent Prescysol developer I have never done a comparison with this developer. Peter clearly states on his website that his alkaline fixer preserves the staining effect.
The effect may indeed be apparent with different films/developers it would be nice if someone could carry out a comprehensive test with various films/staining developers.