Here are a few spectral sensitivities for various imaging processes:-
1) Silver Halide:- PANCHROMATIC
2) Photopolymerization:- 280 - 400 nm
3) Photocross-linking :- 257 - 356 nm
4) Diazo Process :- 350 - 450 nm
5) Blue Print or Cyanotype Uv + Blue Light (450 nm)
6) Kallitype, Van Dyke, Iron/Platinum processes: I haven't any
information on these, but I would hazard a guess that they would be
similar to the Blue Print process
7) Dichromated Colloids:- Gelatine, Gloy, Albumen, Gum Arabic,
Polyvinyl Alcohol, Etc.
According to Kosar spectral sensitivity is influenced little if any by
the nature of the colloid. Quoting from page 73 of 'Light Sensitive
Systems':-
"The spectral sensitivity of dichromated colloid films is not uniform
throughout the visible region.From a maximum of 210 nm it decreases
rapibly near 3320 nm, and then rises to a weaker maximum at 355 nm where
the sensitivity is about one fifth of the sensitivity at 210 nm. Beyond
this second peak, in the visible violet, the sensitivity falls off
rapidly, and in the blue green, more slowly, finally falling to zero at
approximately 580 nm, above 600 nm, dichromated colloids may be
considered insensitive."
Obviously the presence of pigment will also effect the sensivity, as
will pH, and dichromate concentration.
I hope that the above figures, which should be considered as only
approximate, will be of interest.
Cheers,
Alex.
-- Alex Nanson alec@norlex.demon.co.uk Gloucester. UK