I am having a photo book published and am getting some professional help with retouching the images. The guy retouching has his monitor calibrated to 6500 Kelvin at gamma 2.2. Now we are viewing the printed images (rgb printed on a high end epson) under a 5000 K light. They pretty much match what we are seeing on monitor. First question is why do they match given that the monitor is at 6500 k and the viewing light is at 5000 k? Shouldn't the viewing light also be at 6500k?
When viewing scenes or hard-copy reproductions, it is generally assumed that one adapts almost completely to the color and luminance of the prevailing light source. This is likely not the case when soft-copy image displays are viewed. Differences in the degree of chromatic adaptation to hard-copy and soft-copy displays point to two types of chromatic-adaptation mechanisms: sensory and cognitive. Sensory mechanisms are those that act automatically in response to the stimulus, such as retinal gain control. Cognitive mechanisms are those that rely on observers' knowledge of scene content.
The cognitive mechanisms that are largely responsible for chromatic adaption are not as active when viewing a soft-copy. Consequently chromatic adaptation isn't full and a more bluish white point is required to match a D50 light booth to a display.
One should of course always use what works best, but generally a D65 display is somewhat too bluish compared to a D50 box. As Walter already pointed out, as long as both are not in the same field of view, it works pretty well.
You'll probably get a better match with a display at a color temperature between 5600-6000K (5800 average), which is BTW current UGRA recommendation for matching display to hard-copy. But again, just use whatever works best for you.