Training for the Masses: 'OK ... Where Do I Put the Thermometer?'
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| Paul W. Marino |
In this case, the query of where to place the little glass tube is merely a metaphor to introduce an everyday concept of TV production that will knock the socks clean off your feet. So settle down ... tie your shoes securely ... and read on. And on what subject? Color temperature.
Let me explain: Color temperature has to do with the quantity and the quality of the light that a camera has to work with. You can explore this phenomena pretty easily. Take a sheet of paper or cloth that's of an even shade — let's say of blue. Take a look at it in direct sunlight, then in shade.
Next, take a look at it under an incandescent lamp, and then under a flourescent one. Each time, the paper should look slightly different. In direct sunlight, the blue appears bright; in the shade, it appears darker. And the two artificial lights change it even more because they don't put out a full spectrum of light. Rather, they emit specific shades of light.
To the naked eye, this doesn't matter much, but in the TV studio it matters a great deal. Why? Because when you're working with two or more cameras it's important that they all see things the same way. This is accomplished by a procedure known as "white balancing."
White balancing is actually a two-step process that involves pointing the camera at a white card that is flooded with the light that's going to be used during the show. A little switch is thrown, which tells the camera to balance itself. The camera then adjusts its internal workings so that all the white tones it sees are accurate under that temperature.
Next, you press the same switch the other way, causing the camera to close its iris and adjust the black tones. Neat, isn't it? The downside is that if the color temperature changes (say, by the lights being dimmed or brightened) the cameras have to be balanced again. Enter ingenuity! For the past some years now, Northern Berkshire Community Television Corp. has been blessed with a nifty lighting system that uses internal barn doors that can dim or brighten the lights without changing the color temperature!
If this sounds like something you have to understand better, give us a call at 413-663-9006. Or better yet, come and see us in Building 6 in Western Gateway Heritage State Park in North Adams. And don't forget to sign up for a workshop series.
What, after all, is the point of understanding any of this if you don't get to use it? So put your socks back on and get down here!
Paul W. Marino is the production director at NBCTC, the Northern Berkshires public access television station. His column runs once a month.
