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Top 50 Lighting Terms Defined

Lighting terms are often misunderstood due to double meanings and definitions that depend on context. We tackle the top 50.

By David Martin Jacques
September 16, 2013 10:50 am EST

Topics: Tech Tutorial, Lighting-based,
Tags: design, education, installation, lighting, training,

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Once you learn the language of lighting design, you will be able to create and communicate with your fellow theatre artists.

Lighting designers must be able to define and use a dizzying array of technical terms used in the art of theatrical lighting design. As in many languages, the language of lighting design can have some confusing terminology. Some words even have double meanings, and multiple definitions depending on how they are used. It would take a very long article to explain all the technical words used in the theatre. Below are a few of my favorite terms that are sometimes misunderstood.

Additive Color Mixing - This is the way designers mix color in light by combining two or more colors of light in the same area. When two or more wavelengths of colors mix additively, the resulting color is always lighter. When you mix all three primary or secondary colors together at the same intensity, theoretically the resulting color is white.

Atmosphere - This item is used to describe a light cue. It is also used as a general term to describe the density of haze or smoke in the air to reflect light beams.

Automated Light - Also known as "moving light" or "intelligent light" (although I have no idea how a light can be intelligent). This name refers to any fixture where multiple movement parameters can be remotely controlled.

Balcony Rail - A pipe located on the front of the balcony. This position is ideal to fill in the shadows under the eyes with light.

Beam and Field Spreads - The beam of the light is the width from the center of the light (where it is brightest) to the point where the intensity drops off to 50%. The field of the light is the part of the light that is measured from the center of the beam to the point where the intensity drops off to 10%. Due to its' lens arrangement and design, Lekos have predetermined beam and field spreads. The most common are 5, 10, 14, 19, 26, 36, 50, 70, and 90-degree beam spreads, and are identified as such.

Blackout - A lighting cue that brings all the intensity levels to zero. This is usually the light cue placed at the end of the Act or at the end of the show. Shows over!

Bleed Through - This is the effect when light is shifted from the front of a scrim, to the rear of a scrim, illuminating the objects behind the scrim. This can be a powerfully magical effect that makes objects appear behind a curtain.

Booms - These are vertical pipes that are mostly used upstage of the proscenium to provide low to medium side light for the actors. As booms are pipes that are mounted to the floor of the stage, they will block scenic wagons moving on and off stage.

Box Boom - This is a vertical front-of-house lighting position that is located where the audience boxes would be on the left and right sides of the theater. This position is used for front-of-house diagonal side and front light.

Build - A lighting cue that intensifies the atmosphere to support a intensifying mood change or a crescendo in the music.

Bump - A lighting cue on a 0 second count.

Button - A lighting cue that either brightens the overall look or focuses done to a specific point on the stage usually on a very fast count at the very end of a musical number. The times for buttons are usually 0 or 1 second.

Catwalk - This term refers to the bridges used by electricians to hang, circuit, and focus lights. They are usually located above the stage and the audience. For instance, the electricians will use a catwalk to access a front-of-house cove position.

Channel - A predetermined identifier for one or more lighting parameters on a lighting control console. A channel could control intensity, color, pan, tilt, etc, for one or several lighting fixtures. Channel levels are recorded in lighting cues,

Cove - This position refers to the horizontal lighting positions in the ceiling above the audience. This position is sometimes called the "FOH Beam" or "A.P. (anti-proscenium)"

Cue Only - A programming command given after a record command that will record the channel levels in a cue for that cue only. The channels will return to their original levels in subsequent cues.

Delay - A programming command that will delay the execution of a cue or part of a cue after a given time.

Dichroic Filter - Chemically treated glass filter that changes the color of the light by allowing certain wavelengths of light to pass through the glass, and reflecting specific wavelengths of light away from the glass. This color media is used primarily in moving lights. Unlike gels, dichroic filters do not burn or fade.

Diffusion - Softening the beam of light through focus or color media. Next page