[pure-silver] Re: D-76 and variations

The problem with the rise in pH of D-76 with time is due to the
oxidation of hydroquinone.  This is a fairly complex reaction in which
OH- ions are produced.  It has nothing to due with either carbonates or
borax.

-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of John Black
Sent: Monday, November 28, 2005 12:51 PM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: D-76 and variations



>
>
>    The original D-76 formula and Ilford's published formula for ID-11 
> are:
>
> Water (at 125F or 52C)                750.0 ml
> Metol                                   2.0 grams
> Sodium Sulfite, dessicated            100.0 grams
> Hydroquinone                            5.0 grams
> Borax, granulated                       2.0 grams
> Water to make                           1.0 liter
>

Seems like I remember the OLD original prewar formula for D76 was
accelerated with Na Carbonate and had a problem with increasing activity
with aging in solution that was traced to a rise in pH mediated by the
carbonate.  All of which was remedied by switching to borate
accelerators/buffers.  Am I dreaming or was that the case many years
ago?

JB



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