From: Linas Kudzma (lkudzma@earthlink.net)
Date: 03/09/03-06:16:18 PM Z
Eric,
What Erich means is "pure platinum" (no palladium). The so-called
"extravagatype" uses only K2PtCl4 and ammonium ferric oxalate and brush
development with potassium oxalate developer diluted with glycerin. Results
can be beautiful. However, Na2PtCl6 used as a contrast agent precipitates a
portion of the much less soluble (NH4)2PtCl6 which forms in situ. I've
coated such a slurry with OK results (and a contrast boost), but I don't
like the idea of coating a slurry containing an insufficiently soluble Pt
salt.
Linas
----- Original Message -----
From: "Eric Neilsen" <e.neilsen@worldnet.att.net>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Saturday, March 08, 2003 7:03 PM
Subject: RE: platinum questions
> Perhaps you can do two things for me Erich. Please tell us what you
> mean by "real platinum" and how does one get NH4 from sodium and
> potassium? I don't have a copy of TNPP but it is quite impossible to
> make sodium turn into ammonium by putting it in a shared vessel under
> darkroom conditions.
>
> Eric Neilsen Photography
> 4101 Commerce Street
> Suite 9
> Dallas, TX 75226
> http://e.neilsen.home.att.net
> http://ericneilsenphotography.com
>
>
> -----Original Message-----
> From: Erich Camerling [mailto:e.camerling@freeler.nl]
> Sent: Wednesday, March 05, 2003 2:00 PM
> To: alt-photo
> Subject: Re: platinum questions
>
> Kerik,
> With real platinum printing,called *extravagatype* by Sullivan and Weese
> in
> their book "The New Platinum Print",it is impossible to use "Na2"
> (Na2PtCl6)
> as a contrast agent because you will get a precipitate of (NH4)2PtCl6
> before you can coat .
> Erich.
>
>
>
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