U of S | Mailing List Archive | alt-photo-process-l | Re: ferri sesquichlorati

Re: ferri sesquichlorati

Hi Francesc

If what you are looking for is highest sensitivity, that is usually given as
365 nm (I believe something in that area goes for most metals ? Although
several factors affect things... As usual)

I don't have everything here right now, for me this has been more background

Just very quickly put together, this is from something I did some years ago,
the top line shows the absorbency of ferric oxalate (in water), the
following lines/scanns are "during" exposure, each line, moving downwards,
is a doubling of exposure time.


I´ll take down that link in a week or so, are very slowly working on that

(and before anyone asks, no; alcohol sensitisation of platinum printing is
not very practical, as the alcohol tends to evaporate :-)

Ammonium ferric citrate and oxalate have an almost similar absorbency
pattern. (and absorbency does not directly equal sensitivity).

Try google scholar, that would give better results for that kind of
searches, but a university library connection might help to actually get
hold of the search results.

I can recommend a couple of articles on this subject, but they are quite
heavy reading and are not about printing, contact me off list if that is
your taste :-)


On 10/25/06 3:25 AM, "sitgesn1@netscape.net" <sitgesn1@netscape.net> wrote:

> Halvor wrote:
>>> But yes, the most impressive part of ferric chloride is its low
> sensitivity :-)
> (don't think 488 nm would be the optimum for ferric really, have done
> some spectral scanning of AFC and FO and don't think there was much
> absorbency at least, in that area, but I am not too familiar with the
> needs of holography<<
> Halvor
> I'm very much interested in ferric printing processes using ferric
> salts.I have been trying to find through google ferric absorption bands
> between 250-500 nm but without succes.  I understand after reading
> above paragraph you probably have these data. Should it be possible to
> get a copy of ferric salts absorption bands?
> -Francesc
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