U of S | Mailing List Archive | alt-photo-process-l | Re: outdoor gum demo

Re: outdoor gum demo


On Apr 17, 2009, at 12:34 PM, Alberto Novo wrote:

it's very interesting that greenish brown/brownish green/brownish stain
color is pretty effective at blocking UV (visible light DR and UV DR is
different) for pyro-developed silver/gelatin negatives, whereas
"coincidentally" green color is the strongest UV blocker for many inksets
/ printers. Two most different medias (printer ink / stained gelatin)
exhibiting similarities in the same context -> confusing indeed.

IF the UV absorption is extended in the visible range,
there is some absorption *also* of the blue radiation, so that chiefly yellow is transmitted (brown is a dark yellow).
BUT (not a logical variable :-) )
this is not a universal rule (again, think to sun oils...)

Not that I'm interested in pursuing -> just mentioned for the records...