Re: POP process

----- Original Message -----
From: "Loris Medici" <loris_medici@mynet.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Monday, November 08, 2004 10:37 AM
Subject: Re: POP process

> Thanks for the info. Will look for T-55 formula.
>
> I don't know about POP but before I started to tone
> Vandykes in gold, I can say that I never experienced any
> image fading during fixation of untoned images (or my
> observation talent is very poor)... and I was using
> Christopher James' recommendation of fixing in 2%
> anhydrous sodium thiosulfate for not more than 1 minute -
> do you think this is far from being enough? (FWIW, please
> note that I always develop my Vandykes in 2% citric acid -
> I use plain water only for the final wash after
> toning/fixing).
>
> Now, I tone my Vandykes in gold anyway because I like the
> resulting dmax (better).
>
> ----- Original Message -----
> From: "Ryuji Suzuki" <rs@silvergrain.org>
> To: <alt-photo-process-l@sask.usask.ca>;
> <loris_medici@mynet.com>
> Sent: Monday, November 08, 2004 7:45 PM
> Subject: Re: POP process
>
>
>> From: Loris Medici <loris_medici@mynet.com>
>> Subject: Re: POP process
>> Date: Mon, 08 Nov 2004 19:03:47 +0200
>>
>> ... But selenium toner can be made without thiosulfate,
>> for
>> example Kodak formula T-55. Thiosulfate is in KRST to
>> make the toning
>> action rapid. I also make a toner that contains both
>> selenium and
>> ...
>
   Kodak T-55 is a type of Selenium toner made with Sodium
Sulfide. Some of the toning comes from the sulfide. Sulfide
also tones silver halide very readily so this toner is no
better than KRST for use before fixing. It will simply turn
the whole print brown.
   It may help to undestand that Selenium is not a metal as
is often stated. It is related to Sulfur. It has some
characteristics of metals but is different in nature from
Gold or other metals used for toning. Ryuji has very much
more knowledge of chemistry than I do and can probably
explain the differences.

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