RE: Pure Pt printing and solarization..follow up and preliminary conclusions (re-send)

Cor, Are you printing dry or humidified? To increase the speed of pure
platinum try a dry paper around 20%.

Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226
214-827-8301
http://ericneilsenphotography.com
> -----Original Message-----
> From: Breukel, C. (HKG) [mailto:C.Breukel@lumc.nl]
> Sent: Monday, December 12, 2005 7:42 AM
> To: alt-photo-process-l@sask.usask.ca
> Subject: Pure Pt printing and solarization..follow up and
> preliminary conclusions (re-send)
>
>
>
> Hi,
>
> About 2 weeks ago I posted some results on my "home-brewn" Pt
> mixture
> which appeared to solarize easily, printed high contrast (later
> experiments indicated that the solution was only suitable for
> "normal"
> silver gelatine negatives).
>
> Marek suggested that there was perhaps contamination of K2PtCl6
> (Pt(IV))
> in my K2PtCl4 (Pt(II)) preparation, and this Pt(IV) could work
> as a
> contrast agent (as Na2PtCl6 aka Na2 does). K2PtCl6 is only
> slightly
> soluble (Handbook of Chemistry and Physics: at 2degC about 0.5
> gr and at
> 100degC about 5.2 gr in 100 ml water, no data for roomtemp.)
>
> Since I made my K2PtCl4 by reducing K2PtCl6 (not to completion
> to avoid
> reducing to Pt), K2PtCl6 could be present. The obvious step was
> to try
> reducinga sample further. This time some fine black powder
> precipitated
> (Pt), so the reduction of K2PtCl6 was assumed to be complete.
>
> This K2PtCl4 printed as expected and gave nice prints, although
> it still
> has difficulties with an overexposed PyrocatHD negative (a very
> slight
> solarisation and excessive printing times of 40 minutes). The
> same
> negative prints in about 15 min. as a Ziatype in my set-up.
>
> Hope this is of some interest,
>
> Best,
>
> Cor
Received on Tue Dec 13 01:34:55 2005