RE: Pure Pt printing and solarazation

Cor,
For the reduction process you might want to add some extra reducing agent.
This way you will form some metallic Pt that you can filter out of the
solution. Once you see even the small amount of Pt precipitating you know
that you have rediced all the Pt(IV) to Pt(II). That's just a side note. It
might not be your problem at all.
Marek

>From: "Breukel, C. (HKG)" <C.Breukel@lumc.nl>
>Reply-To: alt-photo-process-l@sask.usask.ca
>To: alt-photo-process-l@sask.usask.ca
>Subject: RE: Pure Pt printing and solarazation
>Date: Thu, 01 Dec 2005 15:51:52 +0100
>
>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 Fri Dec 2 08:26:02 2005