Re: Toning kallitypes and vandykes

Sandy,

I don't know how I overlooked this on apug, but thanks
for posting it here as well. The information is very
relevant to some of the work I am doing.

- Randy

--- Sandy King <sanking@clemson.edu> wrote:

> 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 08:07:19 2005