[pure-silver] Re: Phenidone and Dimezone-S Equivalents.

["John Black" <jblack@xxxxxxxxx>]

> I'm about to mix up some phenidone print developers.  I have some
> Dimezone-S, and I've read from a previous thread that the amount of
> Dimezone-S that should be used should be calculated by multiplying the
> amount of phenidone by the ratio of their molecular weights (i.e x1.27).
<snip>

I'm the guy that said it was less active than phenidone.  If I want to use
DS as a substitute for phenidone in a formula, and all else is held constant
(pH, VC, sulfite etc), I have to increase the DS by at least 1.5-2.0X over
phenidone.  That is, if I am using 50mg phenidone per liter, in order to get
the same activity with DS I have to use 75-100mg.  I don't exactly know why
this is true in my case but I have DS from 3 different sources (UK, China
and Germany; one may have originated in India) and they all show the same
activity drop versus phenidone.

Just use phenidone and disolve it in ethylene glycol. It will remain active
for years.  Of course it is always possible that DS and phenidone have
different pH versus activity curves and DS may work fine in a traditionally
very alkaline print developer. All of my data comes from low pH (8.0-8.4)
film developers.

JB





=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your 
account (the same e-mail address and password you set-up when you subscribed,) 
and unsubscribe from there.

• References:
  • [pure-silver] Re: PMK and MCS
    • From: Christopher Woodhouse
  • [pure-silver] Phenidone and Dimezone-S Equivalents.
    • From: john stockdale

Other related posts:

[pure-silver] Phenidone and Dimezone-S Equivalents.

[pure-silver] Re: Phenidone and Dimezone-S Equivalents.

[pure-silver] Re: Phenidone and Dimezone-S Equivalents.