TERMS & DEFINITIONS
Fixture – A device or enclosure hold a bulb or lamp.
Throw – The distance a fixture is designed to concentrate light.
Beam – The size of the throw of the light.
Spot – A fixture and/or bulb designed to give a concentrated light beam sometimes with a very define edge.
Flood or fill – A fixture and/or bulb designed to give a soft and wide beam of light whose edges and defuse (not well defined).
Focus – The ability of a fixture to define the edges of a beam or to change from spot to flood (or fill).
Barn doors – An accessory when installed on the front of a fixture can act like a set of blinders on a horse and prevent light from shining into an area.
Gel – A colored piece of high temperature cellophane which “colors” the light from a fixture.
Gel frame – A metal holder for Gels.
Gobo – A stencil that is inserted into certain types of lights and projects the images that are etched on the Gobo.
Safety – A cable that is required to keep a light from fall in case to becomes detached from it’s mounting.
Bar – A pipe either suspended or raised from a stand to hold lights and/or speakers.
Tree – A “T” shaped set of bars to hold light fixtures.
Truss – A grid like triangular or square structure that can be suspended or held up with vertical pieces of truss.
Grid – A system of trusses either suspended or held up by vertical trusses that contain lighting and/or sound equipment.
Prerig – A truss that has lighting already installed.
Dimmer(s) – A device that adjusts the voltage in order to adjust the intensity of light(s).
Dimmer packs – A set or array of dimmers controlled by a light control board.
Light Control Board – A central control panel that can be manual or programmable
Control Cable – Any cable that is used to control either dimmer packs and/or intelligent light(s).
DMX Cable – A style of control cable (also used in audio).
TYPES OF LIGHTS
Par or Par Can – A fill or spot type of light. The “can” holds the bulb. The style of light depends upon the lamp installed, either flood or spot.
Fresnel (Firnel) – A fixture with a lens. Some Fresnel are adjustable from flood to spot. The light even when set to spot and a defuse (soft) edge. Can use both gels and barn doors with this light.
Ellipsoidal (Lico) – A spot light with both a lens and well defined beam edge. This type of light comes with in many variations. Some have a fixed beam, others have interchangeable lens in order to adjust the size of the beam. These lights can use barn doors, gel and Gobos.
Follow Spot – A manned light with features similar to ellipsoidal’s but controllable by the operator. This type of light normally has multiple gel, a shutter to close the light, an iris to shrink the size of the beam. These lights normally have a focus to sharpen or defuse the edges of the light beam.
Intelligent Light – A general category for lights that have multiple functions and are controlled (or programmed) remotely.
SAFETY
Exit signs – A sign either directing or indicating an exit from a structure or tent. Sign are also required to have a battery backup in case of power outage.
Emergency Lighting – A set of lights which energize when their is a power outage. These lights work on a backup battery.
DISCUSSION ON ADEQUATE LIGHTING
Ellipsoidal – Gobo chart
|
DISTANCE |
VERY WIDE 50 |
WIDE 36 |
MEDIUM 26 |
NARROW 19 |
||||
|
IN FEET |
BEAM |
GOBO |
BEAM |
GOBO |
BEAM |
GOBO |
BEAM |
GOBO |
|
10 |
9.6 |
6.0 |
6.3 |
4.5 |
4.5 |
3.3 |
3.2 |
2.7 |
|
15 |
14.4 |
9.0 |
9.4 |
6.8 |
6.7 |
5.0 |
4.8 |
4.1 |
|
20 |
19.2 |
12.0 |
12.5 |
9.0 |
8.9 |
6.6 |
6.3 |
5.4 |
|
25 |
24.0 |
15.0 |
15.7 |
11.3 |
11.2 |
8.3 |
7.9 |
6.8 |
|
30 |
28.8 |
18.0 |
18.8 |
13.5 |
13.4 |
9.9 |
9.5 |
8.1 |
|
35 |
33.6 |
21.0 |
21.9 |
15.8 |
15.6 |
11.6 |
11.1 |
9.5 |
|
40 |
38.4 |
24.0 |
25.0 |
18.0 |
17.8 |
13.2 |
12.6 |
10.8 |
|
45 |
43.2 |
27.0 |
28.2 |
20.3 |
20.1 |
14.9 |
14.2 |
12.2 |
|
50 |
48.0 |
30.0 |
31.3 |
22.5 |
22.3 |
16.5 |
15.8 |
13.5 |
|
55 |
52.8 |
33.0 |
34.4 |
24.8 |
24.5 |
18.2 |
17.4 |
14.9 |
|
60 |
57.6 |
36.0 |
37.5 |
27.0 |
26.7 |
19.8 |
18.9 |
16.2 |
|
65 |
62.4 |
39.0 |
40.7 |
29.3 |
29.0 |
21.5 |
20.5 |
17.6 |
|
70 |
67.2 |
42.0 |
43.8 |
31.5 |
31.2 |
23.1 |
22.1 |
18.9 |
|
75 |
72.0 |
45.0 |
46.9 |
33.8 |
33.4 |
24.8 |
23.7 |
20.3 |