RE: Pure Pt printing and solarization

Hi Marek,

After doing some more experiments with my Pt solution, I am getting less and less sure about the absence of Pt(IV) in my Pt(II) solution..I now do see isolated black specks, as Jeffrey inquired, these can be the K2PtCl6. And I see a consistent shorter scale on the Stouffer step wedge: a Zia step wedge shows almost all 21 steps distinct, whereas my Pt shows about 8-10 distinct steps (do not have the strips here), and a quite "heavy" PyrocatHD neg, which prints very nice as Zia, it's almost impossible to print the mid-highlights with pure Pt. What I do print looks beautifully separated, very crisp.

So I think you pointed me in a good direction: I will take a small sample of my Pt(II) solution, reduce it further (perhaps until I see some Pt drop out, at least than I am reasonably sure that there is no K2PtCl6 left), and compare it to my present solution.

Perhaps I can than use these 2 solutions as a contrast control set, taking the occasional black specksfor granted..;-)..

Thanks for your input, as well thanks to Jeff and Eric for valuable feedback!

I'll keep you informed,

Best,

Cor

> -----Original Message-----
> From: Marek Matusz [mailto:marekmatusz@hotmail.com]
> Sent: vrijdag 2 december 2005 15:26
> To: alt-photo-process-l@sask.usask.ca
> Subject: 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 Sat Dec 3 03:40:14 2005