Re: "preferred white point" was "The Mystery of Adaptation"

Phil

Have you by the chance published the summary of this study somewhere?

Boris

[EMAIL PROTECTED] (Soluxlamps) wrote in message news:<[EMAIL PROTECTED]>...
> Danny Rich wrote
> 
> >I personally believe that the
> >human observer has not only certain preferred memory colors but also a
> >preferred memory white point which is approximately D65.  But I have no
> >objective data on this only my and other color engineer's anecdotal
> >evidence.
> >
> >Danny Rich
> >
> 
> 
> Danny,
> I am loath to disagree with you, but let me add some anecdotal experience that
> is vrey contrary to your outlook.  
> 
> When Tailored Lighting developed SoLux, we first came out with a bulb to
> simulate direct sunlight color temperature (D50 or "Source B" which are fairly
> close to each other).   That bulb, the 4700K Solux, has technical applications
> as an excellent D50 simulator, but it was NOT well recieved in the art or
> interior lighting markets because it was too "cold."  
> 
> So, we did some tests with a system that allowed us to gradually shift a smooth
> Spectral Power Distribution (SPD) (while maintaining the intensity) so that we
> could change the color temperature continously from 2800K to about 5000K.  We
> took this system and tested it on some of the finest art in the world at the
> National Gallery of Art.  
> 
> The result -- we found that around 3500K (with a smooth SPD) was the
> "preferred" place to view art.  Since then we have found that it is also
> preferred when compared to 4100K or standard halogen (about 3000K) for
> illuminating interiors.  It seems to be very close to the light that occurs at
> the "magic hour" during the day.  
> That is why we developed the 3500K SoLux bulb which has been well recieved by
> the art community.  Note: we have noted a preference shift to a cooler light
> for artwork that is predominated by cooler colors (usually more modern works) -
> up to about 4100K.  
> 
> We also believe that intensity affects this preferred light.  The higher the
> intensity, the higher the preferred color temperature.   This seems to go along
> with what Kruithof found years ago.  
> 
> Based on this work, I do not think that D65 would ever be "preferred" by very
> many people.   I believe it would be seen as very "cold."
> 
> Just thought you might want to add our experience  to your "anecdotal"
> experience.
> 
> Phil Bradfield, Ph. D.
> VP-Tailored Lighting Inc.
> Where SoLux was invented
> www.solux.net
> 800-254-4487
> phil AT solux DOT net