RE: palladium drydown and developer

That's pretty much it.

The term "binder" is used here to include anything to which
image-forming paritcules are bound. In silver-gelatin process, it's
promarily gelatin, but in other non-binder processes it's paper fiber
and paper sizing material.

In silver gelatin printing papers, the drydown was almost eliminated by
use of suitable hardener that limited gelatin swelling to less than 5x,
more commonly between 2x and 3x the dry thickness. In other processes,
the idea is the same, but the drydown can be managed by regulating the
penetration of sensitizer into the sizing material and/or paper fibers.

On Thu, 20 Jul 2006 16:27:00 -0400, "Gawain Weaver"
<gawain.weaver@gmail.com> said:
> My understanding of dry down is that it is only a function of paper
> shrinkage-- as the paper shrinks, the image particles come closer
> together,
> resulting in higher density (both physically and visually). Sizing would
> presumably influence degree of paper expansion and contraction, so the
> influence of sizing would be predicted by this explanation. Are there
> other
> factors or better explanations than this?
>
> Gawain Weaver
>
>
> -----Original Message-----
> From: Ryuji Suzuki [mailto:rs@silvergrain.org]
> Sent: Thursday, July 20, 2006 3:54 PM
> To: alt-photo-process-l@usask.ca
> Subject: Re: palladium drydown and developer
>
>
> On Thu, 20 Jul 2006 14:27:24 -0400 (EDT), TERRYAKING@aol.com said:
>
> > One of the things we found during our retro-invention programme was that
> > the
> > method of sizing can can make a ignificant difference. In fact we have
> > found
> > two methods both of which significantly improve speed and gradation
> > while
> > one reduces the amount of dry down and the other appears to eliminate it
> > completely.
>
> What's so new about it? It's well known that the binder has a great
> influence on the image density and drydown.
>
Received on 07/20/06-02:39:54 PM Z