[alt-photo] Re: gum contrast...

[Paul Viapiano]

Actually, I'm finding out a lot here:

http://pacifier.com/~kthayer/html/Dichromate.html


----- Original Message ----- 
From: "Paul Viapiano" <viapiano at pacbell.net>
To: "The alternative photographic processes mailing list" 
<alt-photo-process-list at lists.altphotolist.org>
Sent: Monday, May 17, 2010 4:00 PM
Subject: [alt-photo] gum contrast...


> Hi all,
>
> Thanks for the comments on my last question. Sodium bisulfite helped 
> restore brighter colors but yes, not overexposing in the first place is 
> good advice.
>
> Riddle me this, sil vous plait: Knowing that decresing dichromate 
> increases contrast, what would be the difference between a mixture of 2:1 
> gum/dichromate and a mixture of 1:1 where the dichromate is 1/2 strength, 
> both at the same exposure time?
>
> Katherine mentions in her website that halving dichromate reduces speed by 
> approx one stop. If you halved the dichromate, and increased the exposure 
> by two, would you effectively get the same print as a 1:1? I'm trying to 
> see relationships in theory here...
>
> Thanks in advance...Paul
> _______________________________________________
> Alt-photo-process-list | http://altphotolist.org/listinfo