Matching north light with fluorescent bulbs

[Marvin Mattelson]

Val, the lights I use are full spectrum. There are many degrees of color rendering accuracy in the full spectrum area. There is a designation called color rendering index or CRI. If a bulb is rated over 90 CRI it's considered full spectrum. The Lumichrome bulbs I use are rated at 98 CRI, the very highest available. Daylight is rated at 100 CRI.

The color of your ceiling and walls shouldn't matter as ling as the bulbs are in white fixtures. If the lights are reflecting directly from the ceiling you would need to employ some sort of reflector housing to eliminate this since the color of a reflective surface will compromise the color temperature of the bulbs you use.

Hope this helps.

You might want to bring some photos of your studio to Atlanta and we can discuss this further.

[Valerie Warner]

Oh you are the bomb! That makes it very clear. I was not giving any credit to the housing/reflectors that the light is mounted in and I will make sure they are white and wide to throw lots of the CRI 98 light.

I will bring pictures of the studio to Atlanta, thanks!

[Tom Edgerton]

Marvin--

I've always understood the temperature of a north light to be around 6500K to 6800K, approximately in the middle between a regular fluorescent light and 5000K.

I've used the Lumichrome tubes in the ceiling of my studio for years, supplementing my northwest window, and found them to be generally very good. However, a complicating factor for me is that when I paint under any single overarching wavelength of light all day, my eyes get tired, especially at night--to the point where color discernment goes completely South. So I've used a cheap reflector on a stand and bounced another wavelength--sometimes regular tungsten household bulbs, sometimes the Sunwave corkscrew bulbs, sometimes blue-coated bulbs (whatever feels right)--off of the ceiling into the overall Lumichrome illumination. It's really just a "trace" of another wavelength, but the mixture helps immensely in avoiding the eye fatigue over long sessions.

Thanks as always for your thorough research and generosity in sharing it.

Best--TE

[Marvin Mattelson]

Tom, I haven't experienced the eye fatigue you describe, but if I do I'll certainly apply your remedy. I'd never have known about this solution if I hadn't shared my knowledge first. What goes around comes around. Thanks!