Digital BW, The Print

Whoops sorry for the earlier post.

Yes exactly.  I guess I was asking a narrower question.  Pop gamma off to
one side for a second.  Ideally one would perfectly match white point with
viewing conditions.  But in the absence of a specific match for a particular
purpose (eg a situation where you know the colour temp of your gallery)
people tend to congregate around general "standards" - not really standards
but practice.  In several places I have read the "standard" for photography
is D65 whereas it is D50 for the graphic arts community.  See X-Rite's site
or here for two examples:

http://www.thechannelinsider.com/article2/0,1759,1734702,00.asp

Here is a selection from the above:

"Most computer and television displays come from the factory set to a
relatively high color temperature, which produces a white with a bit of a
blue cast, similar to "cool white" fluorescent bulbs. This is done because
most displays produce a brighter image at higher color temperatures. The
standard cool white is 9300 K, but many displays come set even higher. For
multimedia, photography and television the standard color temperature is
6500 K, roughly the color of natural daylight. For optimum color accuracy, a
display for these applications needs to be set to a white point of 6500 K.
More precisely to the chromaticity coordinates of CIE Illuminant D65 or
D6500, which corresponds to average natural daylight for an overcast sky at
noon and includes a blue sky component added to a blackbody spectrum.

For many non-imaging computer applications, particularly under typical
office fluorescent lighting, 9300 K is a better choice. Note that there are
other color-temperature standards, for example, 5000 K is used in graphic
arts because it corresponds to typical indoor lighting consisting of a
mixture of incandescent lighting and sunlight. Note also that if an image is
designed or color-balanced at one color temperature and then viewed at a
different color temperature, all of the colors in the image will be shifted
by varying amounts. For example, reds need to be overemphasized in TVs
operated at 9300 K in order to counteract the blue cast imparted to flesh
tones, particularly facial complexions. This so called "red push" introduces
other color errors."

Yet I noticed that the Eye-One and various other software for measuring
colour (such as calibration targets or step wedges) default to D50.
Presumably one would want the same colour temp on the monitor as the colour
temp used to illuminate a test target.  You use D50 Solux lighting.  I am
puzzled at the references to D65 being the "standard" for photography.

Steve


> From: Louis Dina <lbdina@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Sun, 10 Apr 2005 13:56:20 -0000
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: [Digital BW] Re: Color Temp and Gamma for Color Printing
> 
> 
> 
> I forgot to mention one more thing.  A good monitor to print match
> requires that monitor white displayed on the screen be about the same
> brightness level as paper white illuminated by your viewing light.
> If they are very different, things get very skewed.
> 
> Lou