Problems with Flo 3200K bulbs and green color shift (custom White Balance)

[Gene Sung]

I have the Cool Lights Fluorescent CL-455 and the CL-255. Overall, I really like the company and the lights with the 5600k bulbs (accurate color), but I seem to be having problems with the 3200K bulbs when doing a custom white balance, using a Grey Card. I am shooting with a Canon 7D

I attached a group pic. If you look at #2 and #3, lit with the 3200K bulbs, there is a very noticeable color shift towards green when I do a custom white balance. I noticed that if I do the White balance using a White Card (rather than Grey Card), the green is a little less, but still noticeable.

How can I solve this dilemma of the 3200K green shift problem and get accurate colors? Would using Warm Cards, as opposed to a Grey or White card bring up the colors a bit? Or should I tweak the white balance settings after establishing the custom white balance.

Thanks for any advice in solving this problem.

Gene

Note: When using the 7D preset of 4000K (pic #4), the colors looks pretty good (warmer), but I hate to use a preset all the time. With Auto White Balance, it's hit or miss.

 

[Gene Sung]

Dang... I test the white balance under several different types of tungsten lights, and I now realize that it's my 7D that is not recording it correctly, and not the lights. I'm going to test my 7D against my friend 7D and see what happens. Maybe I have an off setting somewhere in the camera, but no matter what I do, my custom balance always skews heavily towards green. Grrrr......

 

[Cool Lights]

The thing to remember is that camera sensors are made to respond to one end of the color temperature spectrum more than the other. I think most sensors these days are tuned to the daylight area. This is most likely the explanation for what you're seeing. In other words, the 7D probably likes daylight better than tungsten color temperatures.

 

[Gene Sung]

You are right Cool Lights. I tested my friends 7D with Tungsten based lights 3200k and yielded the exact same results as my camera -- A white balance that skewed heavily towards green and was not color accurate. 7D custom white balance is very color accurate with daylight 5600k light though, but not 3200K.