Re: DuPont Velour Black AND POP

----- Original Message -----
From: "BOB KISS" <bobkiss@caribsurf.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Monday, July 18, 2005 5:02 AM
Subject: RE: DuPont Velour Black AND POP

> DEAR MARTIN & RICHARD,
> Please note that developer type also influences how much
> fog will occur on
> older papers. For example I have decade old Azo paper
> which appears fogged
> when developed in Dektol but not in Formulary 130. I am
> guessing this has
> to do with whether the developer works on the latent image
> sites on the
> surface of the silver halide crystals or if it has a high
> concentration of
> Sodium Sulfite, a complexing agent, which dissolves some
> of the crystals
> allowing for development of internal latent image sites.
> The relative
> concentration of KBr in the dev also influences the fog
> level.
> Sooooooooo try a few significantly different developers
> and, by all means,
> try Martin's rehalogenating bath.
> ****Martin, I have some old Centennial POP which is
> showing significant fog.
> I understand that it has extremely fine AgX crystals. I
> don't know if they
> use a chloride or bromide salt to make it. Might a
> rehalogenating bath work
> on it? Can you recommend a formula?
> CHEERS!
> BOB

  One reason for this might be that Agfa 130 has much more
Potassium Bromide it in than Dektol/D-72, assuming the
Formulary version is the published formula and that Dektol
is pretty close to D-72. D-72 specifies 1.8 grams per liter
of stock and 130 specifies 5 grams per liter of stock. More
bromide can be added to either. Agfa/Ansco 130 is very
similar to D-72 but has 11 grams per liter of stock of
Glycin added plus the additional bromide.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com