A Primer on Light Color Temperature for Film and Video
In film and video production, a common mistake for amateurs is to ignore the color temperatures of various light sources. I had a filmmaker show me his film, asking for input. The opening scene was a night time exterior with one instrument and shot wide. The next was a daytime scene shot inside the back seat of a car. The director of photography lit them with an incandescent. The result was a very yellow look.
Light is not necessarily “white.” Light changes color when it burns at different degrees. Our sun provides light that is burning at 5600 kelvins. A tungsten light bulb in your house might be at 3200 kelvins. In the old days, this was pretty much it– either your light sources were 3200 or 5600. If you look at a white object with the camera balanced for daylight, and the light source is burning at 3200, the resulting picture will be extremely “warm” or yellow/orange. Conversely, if you balance a white card at 3200 and use the sun as your source, it will look very blue or “cold.”
Twenty years ago, florescent lighting was the bane of filmmakers and video shooters. It doesn’t technically burn and the color is created depending on the coating on the tubes. The most common flo’s resulted in a greenish feel or color. Also, they cycled. I’ve got footage where I left the fluorescent lighting on and when you shuttled the tape fast forward, you could see the color cycle.
But tungsten lights “burn.” They’re incredibly hot. And they drink a lot of electricity. Resourcefulness led the way for flo’s that didn’t cycle and could be colored to match different temperatures. And they provided soft, beautiful lighting. I use a good little flo kit I picked up from Digital Juice, made by Prompter People and I put daylight balanced bulbs in it. When I’m in a tungsten setup, I might use them to simulate sunlight coming through a window.
The latest/greatest are LED light panels. Both Flo’s and LED’s are “cold” meaning they don’t heat up, burning and melting things. You finished shooting, and you cans tart wrapping right away. No instrument cool down need. And LED’s are dimmable, which is a big advantage over the flo’s (although flo’s have some work-arounds).