RE: Pure Pt printing and solarazation

Hi Marek,

I see I did no read carefully enough: you mean that there still might be K2PtCl6 in my pure prep., well K2PtCl6 is slightly soluble in water, unlike Na2 which is quite soluble. I have to ask if growing crystals of K2PtCl4 could incorporate the Pt(IV), I don't know, offhand Iwould say no, the K2PtCl6 has a distinct yellow colour..but perhaps not visible in the red crystals..I'll try to find out..

Best,

Cor

> -----Original Message-----
> From: Marek Matusz [mailto:marekmatusz@hotmail.com]
> Sent: donderdag 1 december 2005 15:24
> To: alt-photo-process-l@sask.usask.ca
> Subject: RE: Pure Pt printing and solarazation
>
>
> Cor,
> How did you make your platinum salt? If it was made by
> reduction of the
> Pt(IV) salt it is possible that you might have some unreduced
> platinum left
> in the solution. It would act as a contrast booster, similar
> to Na2PtCL6
> method used to adjust palladium print contrast. Longer
> exposure time would
> be consistent I think. I have not printed pure Pt, so I am
> not sure how it
> behaves.
> Marek
>
>
> >From: "Breukel, C. (HKG)" <C.Breukel@lumc.nl>
> >Reply-To: alt-photo-process-l@sask.usask.ca
> >To: "Alt-Photo-Process-L (E-mail)"
> <alt-photo-process-l@sask.usask.ca>
> >Subject: Pure Pt printing and solarazation
> >Date: Thu, 01 Dec 2005 10:09:45 +0100
> >
> >Hi,
> >
> >I recently entered the world of pure Pt printing..(caveat: I
> "made" my own
> >K2PtCl4, which is AFAIK quite pure, but I am not 100% sure
> about it, do not
> >have the means to test for impurities)..and as expected: it
> isn't a easy
> >world..;-)..
> >
> >I have tried a few things: Pt & FerricOxalte, Pot.Oxalate as
> developer, and
> >Extravagatype: Pt & AmmoniumFerricOxalate, developed in 1:1
> >glycerol/PotOxalate with a foambrush, both were dried "bone
> dry" with a
> >hairdrier at medium heat (RH in my place around 70%, temp 16degC).
> >
> >Paper: Simili Japon
> >Chemistry: 200 ul K2PtCl4 (say around 4 drops)
> > 200 ul 25% FerricOxalate
> >Negative: 4*5, processed in PyrocatHD
> > Stouffer Stepwedge
> >
> >I observe the following with both approaches:
> >
> >long printing times: about 1-1.5 stops longer compaired with
> a Ziatype
> >(both with a Stouffer stepwedge and a 4*5 neg), which means
> printing times
> >in the range of 25-35 min! (versus a Zia around 9-11
> minutes) with my set
> >up.
> >
> >Reversal/solarization of the deepest blacks & border : they
> turn in a
> >ligther brown versus a a deep brown/black in the detailed
> shadow area.
> >
> >Overal image tone is black brown, the Extravagatype beeing a
> deeper black.
> >
> >I can think of the following things to explain the
> solarization: Stiil too
> >humid? Too little metal? (I can not load more in one coat,
> this amount is
> >already on the edge, the metal solution seems to be at it's
> saturation
> >point, at room temperature it's ok, at 16deC (my darkroom in
> winter time)
> >there are nice red crystals precipitated). Too long a
> printing time? Don't
> >know what to do about that (btw I cool my UV bank with fans).
> >
> >I also tried some Ziatyp with Pt: I used 30 ul Pt, 90 ul
> Cs2PdCl4 and 120
> >ul AFO, dried very quick, printed very humid (with a piece
> of saran wraap
> >to protect the negative. I obtained a nice print, neutral
> grey of tone,
> >nice midtone separation, a bit lower Dmax compaired with the
> Pt print.
> >
> >But the most striking (but not surprising) thing was the
> hughe difference
> >in tonal values. The pure Pt print has almost blocked up
> shadows, and could
> >use some more density in the highlights, wheras the Ziatype
> had very open
> >shadows, good density in the midtones, and a tad to heavy in the
> >highlights. I guess this demonstrates the effect of self
> masking in POP
> >quite nicely. To repeat: I used the same neg for both
> prints: for the pure
> >Pt this neg is too heavy (too much contrast in the print),
> whereas for the
> >Ziatype the neg could use some more density (although this is easily
> >"cured" by adding a litle bit of amm. dichromate).
> >
> >Comments and advice appreciated!
> >
> >Best,
> >
> >Cor
> >
>
>
>
Received on Thu Dec 1 08:52:51 2005