Re: spectral sensitivity of platinum/palladium and cyanotype coatings.

The fact that green negatives are most efficient at blocking UV is
old news for many of us. There are at least three different
approaches that have gone way beyond idle speculation and have proven
this empirically.

Mark Nelson's system, Keith Schreiber's investigations and my Ternary
diagram approach to discerning UV spectral density all generally end
up showing that greenish ink colors tend to be the most efficient at
blocking UV light.

see:

http://www.precisiondigitalnegatives.com/

and

http://www.zianet.com/jkschreiber/articles/1280PyroDigiNegs.html

and

http://www.alternativephotography.com/articles/art056.html

As far as implications for spectral sensitivity of pt/pd, I would
surmise that it says very little. The UV blocking characteristics of
printer ink has more to do with the characteristics of the ink itself
than with the platinum process per se.

In the end, it doesn't really matter, since it is trivial to find out
which colors are most efficient at blocking UV light for your chosen
process.

Clay

Quote:

In an Il Laborario meeting recently, David Harris suggested using
green inks rather than red for making negatives on Translucent II.
This seemed to work very well for platimum/palladium solutions. What
do people consider the implications of this to be for the spectral
sensitivity of platinum/palladium ?
Received on Tue Feb 21 08:12:17 2006