> Bob
> Don't think the "Diafine" is D-23, nor even divided D-23. Good 'ol
> twenny-tree is too soft. Mr. Diafine surely boosts film speed...TX is
> about 1000 or more ISO. The good thing is that ALL films are developed
> at same time/temp and temp isn't that critical. Problem is heightened
> grain and contrast. I've wondered if I could dilute it a bit for lower
> contrast.
> To a certain degree I've wondered if it isn't sort of a divided Rodinol
> in that there is Phenidone in it.
> Jack
>
Jack, are you implying that rodinol contains phenidone? I think its too
old a formula, as I didn't think phenidone came into general use unitl
the 50's in Ilford formulae, even though the first phenidone synthesis
was patented in 1889. I've made rodinol by starting with p-aminophenol
hydrochloride, adding sulfite and then converting to its free base, which
is bisulphited then redissolved with sodium hydroxide. It is finally
made slightly acid with bisulfite to form the concentrated liquid we have
all come to know and love. Do you have a recipe which incorporates
phenidone (1-phenyl-3-pyrazolidone)? If so please post, as I am somewhat
of a Rodinol buff.
Thanks.
John