Dealing with
FLUORESCENT LIGHTING

Color Issues

Light is the visible part of the electromagnetic spectrum. That which we perceive as color is actually different wavelengths of light within this spectrum. "White" light consists of a fairly even distribution of all the frequencies of light in the visible spectrum.

Most sources used in photography radiate a relatively full spectrum of light..

Daylight = Full Spectrum
Tungsten Light = Full Spectrum (but with more red / less blue)
Fluorescent Light = Discontinuous Spectrum.

The simplified diagram above (left) illustrates how a radiant body (such as the sun or a tungsten light) emits light of all colors in various intensities, but in a non-radiant body, such as a fluorescent light source (right) there is a discontinuous spectrum. Little or no light of some frequencies are emitted, whereas there are large amounts ("spikes") of other colors, such as green. This is one reason why fluorescent lights present color problems in photography.  The diagram below, taken from the Guide Book for the Minolta IIIF color meter, shows the spectrum (relative amount of each color-wavelength of light) present in a number of common light sources.  You will notice how even in continuous spectrum sources there are greater and lesser amounts of various wavelengths, but they do not change as abruptly as fluorescent type sources.  This is why fluorescent lamps are sometimes described as being "spiky" sources.

When shooting motion picture film, assuming you provide the timer with a gray card, the overall color of the fluorescent lights can be corrected and the unwanted green timed out. However, it is important to keep in mind that color timing deals with the whole frame. It can be totally effective ONLY when all light sources we wish to correct are the "same" color temperature.  You cannot use different types of lighting (such as tungsten fixtures and fluorescent fixtures) of differing color temperatures to simultaneously light the same frame and expect the lab to be able to correct for ALL of them at once.  They can only adjust to one overall color temperature at a time.

WARNING:

Correcting fluorescent lighting in the lab has an apparent build up of print contrast and is never a total correction. True colors are not accurately rendered over the full spectrum.

Lighting Issues

Fluorescent light is also very flat and usually comes from overhead. This makes it photographically uninteresting and unattractive. To alleviate this problem:

1. Add fill light to the eyes of your subject
2. Key the subject up about ½ stop over the ambient light
3. Separate the subject from the background, usually with a backlight.

Some of the most common fluorescent bulb types:

• warm white
• warm white deluxe
• cool white

Two specialty bulbs that render photographically "correct" color:

• OPTIMA 32 – matches light of 3200K (tungsten balance)
• CHROMA 50 - matches light of 5000K (daylight balance)

Location Documentary Shooting:

Because you need the entire frame to have one overall color balance, all the lights at your location, as well as the units you bring to light with, should be made to color match one another as closely as possible.  Your best method for doing this is usually determined by the strongest light source present.

The question to ask yourself first is "What type of light is most prevalent?"

• Fluorescent?
• Tungsten?
• Daylight? (such as windows or skylights)

Once you have determined this you have two choices:

1. color correct (gel) your tungsten lights to match the ambient light.
2. color correct (gel) the ambient lights to match your tungsten lights.

1 - Match your tungsten lights to the ambient fluorescent

This is usually the most practical solution. If you are shooting in an office building, factory, grocery store or other setting with a large amount of existing, overhead fluorescent lighting, then the time and cost of changing out or gelling the existing tubes to match your tungsten fixtures is usually prohibitive. In this situation a few gels placed over your tungsten lights will allow you to shoot easily while still taking advantage of the existing, ambient light.

The following gels help to correct tungsten fixtures to match some of the more common fluorescent light sources.

Another way to add light to the subject is to use "shop lights," inexpensive fluorescent fixtures you can purchase at hardware stores, such as Home Depot or Lowes. These are commonly available in sizes that hold 2', 4', and 8’ fluorescent tubes. Once on location put the same type of fluorescent tubes into the shop lights as are already in use at your location. Light your subject using the shop lights, filling in the eyes and eliminating the shadows created by the existing, overhead units.  This method guarantees correct color matching since you are using the same, identical lighting units as are already in place at the location.

And, of course, any time you are working under fluorescent light it is VERY important that you shoot a gray card or color chart!  A gray card is the single most important tool you can give the timer for making certain your dailies come back with correct color and exposure.

2 - Match the existing fluorescent tubes to tungsten or existing daylight

Sometimes it is possible, and practical, to gel the existing fluorescent lights to photographically correct color temperatures. This is especially true if the lights are not bare bulbs but are housed in fixtures that have a diffusing tray below them. These types of fixtures are very common (and often easily reachable) in hallways and corridors.

The proper color correction gel (based on the table shown below) can be placed directly in the tray or wrapped individually around each tube. This solution is a good one provided you have only a limited number of lights to gel, the budget to gel them, the ability to reach them and the time to do the work.

Yet another alternative is to completely replace the existing fluorescent tubes with units balanced for tungsten or daylight photography.  Once you finish shooting the color correct tubes are removed and can be reused on many other locations, making this a cost efficient solution in the long run. As with gels, however, you must be able to reach the units, have the time to do the work and the budget to purchase proper color temperature lights.

There are three commonly used camera filters for dealing with fluorescent lighting.

1. FL-B filter - Corrects fluorescent for Tungsten balanced film.
2. FL-D filter - Corrects fluorescent for Daylight balanced film.
3. 30M CC Filter - A Magenta Color Compensating filter.

There are several considerations that often make using filters on the camera impractical.

1) Light Loss – The camera filters used for color correction each have a very large light loss associated with them. This loss is usually greater than you can afford when shooting indoors under fluorescent lights.

2) Does Not Balance the Scene – A camera filter does not alleviate the problem of matching your lights to the existing fluorescents. You still must match the lights, adding gels, resulting in even more light loss.

For these reasons color correction on the camera, while it can be done, is generally regarded as an impractical solution.

Flicker Issues

Fluorescent light fixtures, like HMI lights, oscillate at specific frequencies.  This means that when shooting at non-standard frame rates (other than 24 or 30 fps) you may get a visible pulsing, or "flicker" in the light.  This can also happen if you adjust the shutter speed of your camera to something other than the standard.  The rate of flicker varies with the light but it's important to be aware of this and be careful when shooting off speed (slow motion or fast motion), or changing your shutter, to avoid getting unwanted variations in brightness.

The following HMI Safe Camera Speeds are usually also safe Frame Per Second rates for shooting under fluorescent lighting.

Shooting under fluorescent lights at speeds other than those listed above MAY result in flicker issues.

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This page last updated
12 January 2005-rev.2

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