Tiffen Camera Filters manual Mixed Lighting Situations, Color-Grad Gradated Color Filters

Fluorescent and Other Discontinuous Spectra Lighting Correction

Since filters never actually add color, but only absorb certain wavelengths to increase the relative proportion of others, the original light source must have the colors you want in it to start with. Some sources are totally deficient in certain wavelengths, which cannot be added back using only filters. This is particularly true of many types of metal halide lighting. With other lighting types, such as fluorescent, color temperature measurements may not provide the correct filter requirements since color temperature theory is based on having a continuous spectrum, meaning light at all wavelengths. It is possible for a light source to have a sufficient spectral distribution to emulate a correctable color temperature when so measured, but its effect on film can be very different.

Fluorescent lighting generally produces a greenish color overcast. Each of the many lamp types varies in color, and it can be difficult to know the precise correction even with a color temperature meter, a set of CC filters, and running some tests. There is available, however, a filter type developed as an average correction for the most commonly encountered fluorescent lamps.

As produced by Tiffen, this filter is called the FL-D®, for use with daylight corrected media, or the FL-B®, for use with tungsten corrected media. Both are designed to yield good-to-excellent color under fluorescents, without the need for a meter and a variety of CC filters.

Mixed Lighting Situations

A question often arises of what to do when there is more than one type of lighting used in a scene. The key to this is to first try to make all the light sources behave the same. That is, to choose one that predominates, correct the camera for that, and correct the other lighting with 'gel' filters made for them. You can convert daylight coming through a window with a gel placed over the window, that will make it a similar color temperature as the predominant tungsten, or even fluorescent, lighting inside. Then correct the camera for that type of light. There are many such combinations that will work, which one to choose is often a matter of economics. Filtering a factory of fluorescents with gels, or filter tubes, may cost far more than just gelling up the occasional window.

If there is no way to correct all the lights for one color temperature, try to minimize the intrusion of those for which you cannot correct to the camera. Sometimes, this can be used to advantage. The cool blue light from outdoors through a window can make the tungsten-lit interior seem that much warmer, and cozier. Once 'normal' color is within reach, frequently a variation can be even better. It all depends on your purpose, and the story you are telling.

Color-Grad® Gradated Color Filters

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