Digital BW, The Print

> I am puzzled at the references to D65 being the "standard" for 
photography.

Join the crowd.  The theory goes that human vision developed based on 
normal daylight, which itself is a moving target, depending on the 
time of day, time of year, atmospheric haze, humidity, etc.  The good 
news is that the eye adapts pretty well to changes in color 
temperature.  That is also the bad news.  

A color consultant friend of mine has a viewing box with three 
different lights, each partitioned off from one another.  He placed 3 
identical images into each partition and turned on the viewing lights 
in a dim room.  One light was tungsten, one fluorescent, and one 
D50.  In this situation, they eye cannot adapt, since all three are 
displaying at the same time, with light baffles preventing light 
bleeed between partitions.  The difference in the images is 
incredible.  In my office, I have a solux D50 lamp and some tungsten 
lighting (which is usually turned off).  Moving a color print quickly 
from one light source to the other shows shifts in color, but the eye 
adapts so quickly, it is far less dramatic.  

When comparing an image on a monitor to hard copy color print, you 
naturally shift your attention between the two pretty quickly.  But 
there is one huge difference.  In the print, you are viewing light 
being reflected from your paper base and pigment or dye ink.  In the 
case of the monitor, the light source IS the image.  Many people 
maintain that the eye's adaptability allows for the use of D65 for 
proofing purposes, and if that works for them, great.  I struggled 
with this for a year, and finally settle on 5500K.  I would have 
preferred to stick with D65 since both sRGB (the default internet 
standard) and Adobe RGB have a 6500K white point.  But it wasn't 
until I recalibrated my monitor to 5500K that I was happy.

That is different from the subject of viewing an image in 
uncontrolled lighting or museum lighting.  Many museaums use 3500-
3600K lighting (see www.solux.net), but that varies all over the 
place.  I have always tried to find a compromise for unknown lighting 
conditions.  I don't like using incandescent balanced profiles for 
color printing, since incandescent light is so deficient in blue and 
I think the prints look lousy.  Whether the best compromise or not, I 
sometimes choose F2 (Cool White Fluorescent) for profile creation 
when I want a print that will work well in mixed lighting or unknown 
situations.  It is a compromise between D50 and the much warmer 
incandescent.  But most of my work is based on a 5000K viewing light 
source.  Here is what Gretag has in their help file regarding F2 and 
F11 light sources:

"The light sources F2 (CWF) and F11 (TL84) represent typical spectral 
power distributions for various types of fluorescent sources. F2 
(CWF) are cool-white fluorescents with a color temperature of 4230 K. 
F11 (TL84) represents a triband fluorescent source with a color 
temperature of 4000 K."

ProfileMaker allows me to build a color profile optimized for a given 
viewing light source.  

Hope this sheds a little more "light" on the subject.  

Lou