Digital BW, The Print

In a message dated 1/30/07 1:27:20 PM, evogel@... writes:


> Thanks David. Wasn't really suggesting (cold) north light as a good source 
> for these purposes, but it is significant historically.
> 

Yes, and quite interesting in terms of interpreting color intent in historic 
paintings. It has a factor more directly related to this list as well: papers 
with artificial brighteners may look quite similar to non-brightened papers in 
lights low in UV and low in blue (such as tungten and other incandescents); 
but the same papers compared under north light look REALLY different, due to 
increased blue light (and if the glazing isn't UV resistant, from increased UV 
components exciting the brighteners as well). This factor is often confused 
with illuminant metamerism; but its not actually related. So I tend to note 
"illuminant metamerism and OBA excitation" as a pair of factors, but no one seems 
to 'get' the second one, so perhaps we need a more easily understood name for 
it...

C. David Tobie
Product Technology Manager
ColorVision Business Unit
Datacolor Inc.
CDTobie@...
www.colorvision.com


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