Don't tell the police...I poisoned my lights

As any of you who have shot in a corporate or industrial setting can attest, as soon as you try to add light to any interior scene, overhead flourescents become the bane of your existence. Most standard flourescent bulbs have a green color cast that we don't see normally, but our good friend the CCD or CMOS picks it up quite nicely. You can color balance to flourescents, but as soon as you start adding tungsten or daylight lamps, you've got a manage a trois of pain on your hands.

The way I've usually handled this in the past, is to not handle it. Guiltily, I'd just light my subject, and if I had time, I'd add the same colored light (usually tungsten) to the background to try and drown out the flourescents. Sometimes this works, but usually I'm left with a background that has a slight green color cast.

The ways to fix the problem are pretty logical. Basically, unite your color casts...either gel all of your flourescents to match your lights, or vice versa. Depending on your location, it may be completely impractical to gel every overhead light to match your subject lighting, which brings us to the subject of "poisoning" your lights.

When I first heard this term on Creative Cow, I had to be the idiot in the forum who asked, "what's that?", but I got my answer. Whether you're on set or color correcting in post, if you want to remove a color cast, you remove the predominant color by adding its opposite color on the color wheel. If you look at the color wheel, green and magenta sit directly opposite. When dealing with flourescents and a green color cast, you either add a magenta gel (minus green gels) to the flourescent, or "poison" your lights with green (plus green gels).

For our shoot on Thursday, we shot in a hallway in pediatrics. I had neither enough gels, nor enough time, to gel all of the overheads, so I decided to finally experiment with poisoning my key light. Last year I bought a good assortment of large Lee gels in a roll-up pack from Film Tools that included minus and plus green gels in a variety of strengths (1/8, 1/4, 1/2, full). I lit our subject with my usual two layers of diffusion, and poisoned my Rifa 55 with a 1/8 plus green inside the softbox. We filled him with reflected light and used a Litepanels Micro with a full CTO gel as a kicker. For background lighting, I used a single Lowel Omni light for the screen-right wall and put two Tota lights 6' down on either side of the perpendicular hall in the distance. I white balanced to a combination of the key and overhead light; this gave my subject and foreground hallway a neutral color cast, and let the background and kicker go slightly warm (gold-red from the color of the ungelled tungsten lights). I've been using a similar combination in daylight settings by lighting my subject with soft daylight and using ungelled tungsten lights for warm accents. Sometimes the tungstens can go too warm, but I'm still playing with it.

Comment with your thoughts on this setup or your own experiences with mixed color temperatures...or blame me for wasting your time by forcing you to read an uber-boring blog about lighting. Thanks for reading, anyway.