From: Linas Kudzma (lkudzma@earthlink.net)
Date: 01/16/02-08:20:40 PM Z
Witho,
I have not done extensive tests, but I have done some, and can say with
absolute certainty that the so called NA2 platinum (Na2PtCl6) available
from B&S raises contrast considerably more that "normal" platinum. In a
test with 1:1 ratios of Pd/Pt, with each type of platinum, the so called
"NA2" complex gave a 3-4 step compresion of the scale when printing a
stouffer step tablet.
The chemical explanation offered in the technical paper at the B&S site
makes perfect sense to me. It takes twice the amount of ferrous oxalate to
reduce the Pt(IV) of the "NA2" complex to metalic platinum Pt(0). The
Pt(IV) complex uses up the available ferrous oxalate rapidly in areas of
lower exposure, and this compreses the scale.
Linas
> [Original Message]
> From: Witho Worms en Jorien van Santen <verzet13@xs4all.nl>
> To: <lkudzma@earthlink.net>
> Date: 1/16/2002 2:52:22 AM
> Subject: Re: Papers
>
> I am curious if anyone has researched this contrasting agent except for
> Sullivan ? I was not able to detect significant changes in contrast with
> this product.
> As far as I know and experienced the contrast is not more influenced than
by
> adding just the 'normal' platinum solution to the palladium.
>
> Witho
>
>
> ----- Original Message -----
> From: "Linas Kudzma" <lkudzma@earthlink.net>
> To: "alt-photo-process-l" <alt-photo-process-l@skyway.usask.ca>
> Sent: Wednesday, January 16, 2002 4:13 AM
> Subject: Re: Papers
>
>
> > Wendy,
> > What I was talking about was using what B&S calls NA2 platinum as a
> > contrast agent in place of B&S Sol#2. There is a good technical paper
> about
> > this special platinum complex on the B&S web site.
> >
> > I'm surprised you can hang the sheets with B&S Sol#2 overnight. I found
> > that anything with chlorate (as in sol#2) needed to be used promptly (a
> few
> > hours). It may be paper dependant? I don't use Platine.
> >
> > Linas
> >
> >
> > > [Original Message]
> > > From: Wendy Gollihue <wgolli@flash.net>
> > > To: <lkudzma@earthlink.net>
> > > Date: 1/15/2002 1:26:06 PM
> > > Subject: Re: Papers
> > >
> > > Linas,
> >
> > >
> >
> > > I use the B&S palladium solution no. 3 that uses NaCl. I use the
> Ferric
> >
> > > oxalates 1 $2 from B&S at 27%.
> >
> > >
> >
> > > Is your finding also true with palladium as the component. I truly
have
> > had
> >
> > > no problems hanging it (platine) all night in the dark but will listen
> and
> >
> > > am willing to change to prevent upcoming difficulties that others have
> >
> > > experienced.
> >
> > >
> >
> > > Wendy (TX)
> >
> > >
> >
> > > ----- Original Message -----
> >
> > > From: "Linas Kudzma" <lkudzma@earthlink.net>
> >
> > > To: "alt-photo-process-l" <alt-photo-process-l@sask.usask.ca>
> >
> > > Sent: Monday, January 14, 2002 10:38 PM
> >
> > > Subject: Re: Papers
> >
> > >
> >
> > >
> >
> > > | Carl,
> >
> > > | Paper coated with only FeOx and metals, with the Pt component
being
> >
> > > | Na2PtCl6, can sit in the dark for days without any bad effect. I'm
> using
> >
> > > | Na2PtCl6 (sodium chloroplatiATE) as the contrast agent (typically
20%
> of
> >
> > > | the metals). In fact, sometimes I like the prints better from such
> > paper
> >
> > > | that sat in the dark overnight. Maybe this is due to a slower, more
> even
> >
> > > | drying? This is for DOP prints on Cranes Cover 90 Natural.
> >
> > > |
> >
> > > | Previously, when I used chlorate for contrast, letting paper sit
> > overnight
> >
> > > | was not possible. This was without a doubt due to side reactions of
> the
> >
> > > | chlorate, which is a very reactive oxidizer. The Na2PtCl6 salt is
very
> >
> > > | stable and a nice contrast agent.
> >
> > > |
> >
> > > | Linas
> >
> > > |
> >
> > > | > [Original Message]
> >
> > > | > From: Carl Weese <cweese@earthlink.net>
> >
> > > | > To: <alt-photo-process-l@sask.usask.ca>
> >
> > > | > Date: 1/14/2002 12:35:02 PM
> >
> > > | > Subject: Re: Papers
> >
> > > | >
> >
> > > | >
> >
> > > |
> >
> > > | > > Wendy: Internally sized. Very textured surface -- not good or
> bad,
> >
> > > | just a
> >
> > > |
> >
> > > | > > question of whether you want that or not for a given image.
> Tough,
> >
> > > | heavy
> >
> > > |
> >
> > > | > > paper. YOU HAVE TO "RE-ACIDIFY" IT for pt/pd printing,
> >
> > > |
> >
> > > | >
> >
> > > |
> >
> > > |
> >
> > > |
> >
> >
> >
> > Linas Kudzma
> >
> >
> >
> >
Linas Kudzma
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