What are we talking about here...? (aging of D-76)

[Arvee]

Thank you, everyone, for the information. With all this data I have come to the realization that I should be mixing the D76d or Konica SD 28 version to avoid the pH shift problem.

Thanks again!

 

[momonga]

I think you should try the D76h formula, the one without hydroquinone. I used it for a while instead of the standard formula, and it gave very similar results, in terms of film speed and developing times. After all, it means one less chemical to buy and stock.

However, I have to add that I always used it one shot and diluted, usually 1+3. I suspect that the synergy of the metol-hydroquinone pair is necessary for D76 when the stock solution is reused.

 

[dancqu]

Not true, the borax is to counteract
the acidity of the Metol.

As though the more alkaline 100 grams of sodium sulfite
have no effect in countering metols acidity. That IIRC 2
grams of borax I maintain were included in the early
version of D-76 to help steady the ph.

I believe the tetraborate, borax, is slowly converted to
the metaborate by hydroxyl ion. Those being produced
according to the reaction PE mentioned in an earlier
post. The metaborate is likely a little more alkaline
than the sulfite. If hydroxyl ion build up went
unabated ph could rise much more.

I wondered for years why that pinch of
borax in D-76. Dan