Quote Originally Posted by Snapshot View Post
Shorter wash times and less film swelling are two advantages that I'm aware of for alkaline fixers. In addition, if you plan on using staining developers, having an alkaline fixer becomes vital in retaining image stain. As for the advantages of acid fixers, I'm not aware of any other than the chemistry is ubiquitous and perhaps less expensive.
Actually, alkaline fixers have shorter wash times due to greater film swelling. The chemistry diffuses out of the coating faster and the wash water diffuses in faster.

Acid fixers can easily be made hardening fixers, and in any event leave films and papers less swollen and harder. So with softer film or paper products, an acid fixer is generally better than an alkaline fixer.