Re: Toning kallitypes and vandykes

Hi Sandy,

Biologist here, not a chemist, but from what little
background I have, I'd say the only options would be
raising the concentration of palladium or raising the
temperature (well, maybe pH and type of palladium salt
would affect it too, but I have no suggestions about
direction here). But, and here's where my ignorance
may show, because the reaction is yielding a solid
whose crystal size affects the look of the print,
changing the rate of reaction may have consequences
for the look of the print, no?

David Barker

--- Sandy King <sanking@CLEMSON.EDU> wrote:

>
> The replacement of silver with palladium ranged from
> less than 20% at
> 2.5 minutes to approximately 60% at 20 minutes.
>
> I would like to find a way to accelerate the process
> to reach about
> 90% in 10 minutes.
>
> Sandy
>
>
>
>
>
>
> >...what was the percentage of replacement after 20
> minutes, if you
> >don't mind me asking? 50? More than 80? Close to
> 100?
> >
> >~m
> >
> >----- Original Message -----
> >From: <mailto:sanking@clemson.edu>Sandy King
> >To:
>
><mailto:alt-photo-process-l@sask.usask.ca>alt-photo-process-l@sask.usask.ca
> >Sent: Sunday, November 13, 2005 10:26 PM
> >Subject: Toning kallitypes and vandykes
> >
> >I posted the following message over on apug.org but
> so far have
> >gotten zero response. Hope someone here can offer
> some advice.
> >
> >Basically the situation is this. I interested the
> folks in
> >photographic conservation at the Getty with the
> issue of toning
> >kallitypes with pallaidum and platinum,
> specifically. Preliminary
> >spectra analyis in their lab has confirmed that
> toning a kallitype
> >(and I believe the same would apply to vandyke)
> with palladium or
> >platinum results in replacement of the silver by
> the more noble
> >metal, adding much permanence to the print.
> >
> >The toning formula used for the tests was 5 grams
> of 20% palladium
> >chloride solution plus 5 grams of citric acid in
> one liter of water,
> >and I did toned 5X7 test samples for 2.5, 5, 10 and
> 20 minutes,
> >using just enough of the toner to cover the surface
> of the print in
> >flat bottom tray. That turns out to be about 50ml
> of solution for a
> >5X7" print.
> >
> >What the tests showed was that the efficiency of
> toning in terms of
> >the percentage of replacement of the silver with
> palladium is time
> >dependent, i.e. a toning time of 20 minute results
> in a much higher
> >percentage of replacement than toning for 5
> minutes. This leads me
> >to a question that I hope some of the chemists on
> the list might be
> >able to answer. Does anyone have any idea how I
> might adjust the
> >toning formula formula above to make it faster
> acting?
> >
> >Sandy
>

        
                
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Received on Mon Nov 14 13:04:22 2005