From: Clay (wcharmon@wt.net)
Date: 12/15/02-04:52:06 PM Z
This is according to Anchell ( Moses of film developing?) : pg 42
He states (and I paraphrase grossly) that fresh D-76 has a pH of about
8.3, and the hydroquinone in the formula is essentially inactive. With
age, the pH will rise as high as 9, which will activate the
hydroquinone and make the developer 'hotter'. Thus the modification for
a mix-it-yourself D-76H: drop the hydroquinone completely, and just mix
2.5 g metol
100 g sodium sulfite
2 g borax decahydrate
per liter of water.
I'm quoting from the book here, and can't claim to have done all the
tests about pH myself. But I do know that the D-76H behaves identically
to the yellow packaged stuff.
Clay
D-76
On Sunday, December 15, 2002, at 04:29 PM, Christina Z. Anderson wrote:
> Bear in mind that D-76 has a rather short shelf life and *gains*
>> activity as it ages. It's best to mix only as much as you'll use in a
> couple
>> weeks time.---Carl
>
> Say what???? Please explain as to why and how much activity are we
> talking
> about in percentages, for instance.
> Chris
>>
>
>
This archive was generated by hypermail 2.1.5 : 01/31/03-09:31:25 AM Z CST