Alberto,
I was trying to point out that what Willis described in his patent is totally different from what we call satista today. The only thing in common is that the end result image is composed from silver and platinum.
Nowhere in his US patent do I see a description of applying a mixture of ferric ammonim oxalate and platinum salts, exposing the image and development in silver nitrate.
By the way I am not claiming that I invented the process either. I do not have any notes on the sources that I used when I first became interested in it. I checked on the printed sources that I could find, internet searches, etc.
Marek
> Date: Mon, 25 May 2009 08:46:40 +0200
> From: alt.list@albertonovo.it
> Subject: Re: argentotype again
> To: alt-photo-process-l@usask.ca
>
> Marek,
> I regret for this late reply. I was without a PC from Thursday.
>
> > I you read Willis original patent, which I can't remember if it is dated 1913 or not, the process that he describes as satista (and I am not sure if he uses that name or not) is not what we call "satista now".
>
> The date are a little confusing: US patent is 1914 (application date
> September 22th, 1913), while the UK one is called 1913 (appl. date September
> 4th, 1913; accepted Sept. 3rd, 1914)
>
> Willis does not describe his process as "satista", but I have found a
> general agreement on this name. See for example:
> Barro L. "The Deterioration of Paul Strand’s Silver-Platinum Prints",
> Abstracts from the Photographic Materials Group of the A.I.C. Annual
> Meeting, San Juan, Puerto Rico 2003
> (http://aic.stanford.edu/sg/pmg/images/abstractswintermeeting.pdf), AND the
> references therein.
>
> > His process involves sensitising silver halide emulsion with platinum, exposure with UV and development in POTA developer. I tried sensitising silver chloride paper (Forte wt) with Pt salts and it workes OK. I need to reread the patent again as it has been a few years.
>
> "The paper first of all receives a coating of chloride of silver which may
> be applied or attached to the surface as an emulsion in gelatine or other
> suitable medium or formed on the surface as an emulsion in gelatine or other
> suitable medium or formed on the surface by the well known process of double
> decomposition" (page 2, row 22-25 in the 1913 UK patent 20,022; page 1, row
> 105-110 in the US patent 1,120,580). So not only a silver chloride gelatine
> paper, but also a well washed sensitized salted paper.
> POTA= potassium oxalate or phenidone+sodium sulphite? I suppose you are
> referring to the first (as in Willis' patent).
>
> > I never followed his recipe as described in the patent, but I would think it would work OK as my crude attemt to sensitize commercial paper gave decent results.
>
> Your recipe (development in 4% silver nitrate) is what Dick Sullivan
> suggested I believe in 2000 (see a date in his article), calling it
> "satista+": http://www.bostick-sullivan.com/articles/satista.html
>
> Alberto
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