Digital BW, The Print

Steve,

You've simplified that far too much, I think. Have a look at

http://www.wilhelm-research.com/pdf/is_t/WIR_ISTpaper_2002_02_HW.pdf

and you will see that the current WIR 'endpoint' is based on about 17 
different endpoints that are considered visually equal and easily 
noticeable. These range from 12% differences in colors that we are very 
sensitive to, up to  35% changes in colors that we are not so sensitive to. 
It's quite a good article, pointing out some of the variables that most 
people never think about. For instance, how you dry a print and for how long 
before exposing it to light can have a very big effect on fading! And 
different densities of ink react differently to light fading.

Bob Frost.

----- Original Message ----- 
From: "Steve Kale" <stevekale@...>


And who would be happy with a Wilhelm stop value of a fade of 30%?  I'd
consider a print to have "faded" well before then.