[Chris Saper]

Marvin, I unfortuntely do not know the specifcs with regard to CRI, although from what I have read is it extremely important.

There is enormous variability in the range of Kelvin temperatures, even controlling for the time of day. Temperatures are dramatically affected by atmospheric conditions, humidity, and altitude. Research I have done with respect to general Kelvin temperatures indicates generally that the light at noon is about 6500 degrees K, in sunlight.

North light conditions that would be as you are describing, would be light uninfluenced by direct sunlight. At noon the temperature could well exceed 15,000 degrees K, but that would be more characteristic of somewhere like Taos, with low humidity, high altitude and cloudless skies. In New York City, I would have to presume the temperature is much lower...salt air, lots of humidity, pollution...all things that influence the temperature of light.

If my memory serves me correctly, it is possible to measure Kelvin temperature for a specific geographic area (of course it would need to include assumtions about the atmospheric conditions), if you indeed want to pursue lighting that would mimic what you would normally have, given the location of your studio. This would be practical if you found yourself combining natural daylight and studio light. If I can recall how you might go about measuring specific Kelvin temperatures, I'll post it...it's been a while.

I am not aware of any manufactured bulbs that are rated at high K temperatures, but there certainly may be some. As I only paint in nautral daylight, I haven't had reason to look. Of the three bulbs you mentioned, I'd presume the higher rated temperature would be preferable to the 5000 K bulbs...it may not, however be enough a difference to appreciably impact choices you might make in your paintings.