RE: Toning kallitypes and vandykes

Toning kallitypes and vandykesSandy,

With gold, isn't the rate of toning and particle size affected by the
solution's pH. It needs to be slightly acidic for reasons I forget, with
gold at any rate, but toning is faster and the colour is supposed to be
bluer as the pH is higher (less acidic). That's what I remember, anyway.
Maybe would give you some control with Pd?

Liam
  -----Original Message-----
  From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
  Sent: 14 November 2005 06:01
  To: alt-photo-process-l@sask.usask.ca
  Subject: Re: Toning kallitypes and vandykes

  ...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: Sandy King
    To: 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
Received on Mon Nov 14 12:45:08 2005