Spray booth lighting

Which type of bulb provides the best light for a spray booth? June 5, 2001

In my new spray booth, I have 6 explosion-proof fluorescent fixtures that take 3 of the 4' long tubes each. What are the best bulbs to install in them? Is the light better if you purchase the more expensive bulbs?

Forum Responses
We used the cool white bulbs (cheap) for years. Last year, we put in a few warm and daylight bulbs, and they are a lot better. Also, we do a little staining and touch up in our booth, and these bulbs make for better color matching.

Go out and buy full spectrum fluorescent tubes. Most of these run around 7-12 bucks a piece, but it will pay off in the long run!

Bob Niemeyer, forum technical advisor

Ever finish a piece in your booth and find it was 2-4 shades darker or lighter than under the customer's lighting? Use as many light sources as possible. My favorites are halogen lamps set as background light, with the fluorescent natural light bulbs as a work light. Color falsing is endemic to finishing. I always take a sample into daylight, or under an incandescent, just to correct color value.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor S:
Working in the lighting industry for close to 15 years now, one of the many problems with color matching, etc is the fact that many light sources fail to match that of natural daylight. Bearing this in mind, a high color rendering lamp, be it fluorescent or metal halide, is the better option. Halogen/warm white lamps produce a golden glow (which is what we call color temperature) that can at times distort the appearance.

Tri-phosphor fluorescents, be they daylight or cool white, have a higher color temp or are whiter. Then match that with a high CRI (color rendering index - the reproduction of colors). There are daylight tubes available with a CRI in excess of 90 (100 is natural daylight).

Two basic things to remember:
Color temp - How we see the light.
Color rendering - How the light reproduces the colors.

Comment from contributor E:
Simple explanation of FL tubes to use:
Color temperature = 5000 degK
CRI = 90%