Gerald, there's a few myths about Phenidone because it's a generic family of developing agents and there are variants so much of what's been written in some books should be taken with a piece of salt.
Phenidone keeps extremely well in powder form, certainly over 45 years, which is not what's written by some authors, it keeps reasonably well in alkali solution. The myths come from Ilfords early experiences from the 40's to very early 1950's, but by the time it was in commercial production (1953/4) the Phenidone being sold was very much more stable in alkali solution.
I use Phenidone in almost all my developers with no stability issues, my original large batch was (bought around 1976) was stamped with Ilfords 1962 code, I only finished it 3 or 4 years ago but there was no differences whatso ever when I switched to newer Phenidone.
Haist's book misses out much of the other parallel research taking place elsewhere as it hadn't been (or was) published when Haist wrote his book but it's a place to start. Gerge Wakefield wrote a good review of the then current research into Monobaths in a British Journal of Photography article around 1976'ish.
My own experience was that Phenidone kept well in FX-6a or equivalents, we kept stock solutions on the shelf for months with no deterioration.
Ian
