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WPI Technical Theatre Handbook: Glass, Gelatine and Plastics
 
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Glass, Gelatine and Plastics

Several methods exist for changing the color of light that lighting instruments project. Most of these methods involve the placement of color media in front of the instrument. The most familiar of these methods involves the use of tinted glass. This is a reasonably functional method, but doesn't prove cost-effective or practical when a large variety of colors are desired.

!sX The next most common method involves a material known as gelatine, or less formally, gel. Gel is made from synthetic dyes mixed with animal or plant jelly, and because of its makeup has many negative side-effects. The main problem with gel is that it fades rapidly under high-intensity, high-heat lighting instruments. Also, gel becomes brittle over time and is destroyed when it comes in contact with water. This is the primary reason that plastics are used to accomplish the same task. Acetate or polyester, in combination with synthetic dyes, make up what most modern lighting designers and technicians refer to when speaking of ``gel'' in the noun form. Plastic works reasonably well as a color media, but still suffers from fading, and tends to warp or burn out after a period of time. Dark colors such as blues tend to be more susceptible to these problems than lighter colors.

Several companies sell color media, the most common of which are Rosco (under the trade names Roscolene and Roscolux), GAM, and Lee. Swatchbooks that contain samples of color media are generally available free of charge from the companies or their distributors. Each company has their own scheme for numbering their colors. For example, GAM 250, Lee 106, Roscolene 823, and Roscolux 27 are all approximately the same pure red color.

Plastic color gel typically is purchased in large sheets (approximately 2 feet by 2 feet), and usually need to be cut down to fit into the color frame for an instrument (see figure 5.11). At WPI, most gels are kept for later use, so it is very important that they be marked with a grease pencil after they have been cut. Typically the marking includes an abbreviation of the manufacturer name and the color number.

Figure 5.11: A typical color frame, used to support a cut piece of color media on the front a lighting instrument.
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next up previous contents index
Next: Dichroic Color Filters Up: Practical Use of Color Previous: Practical Use of Color   Contents   Index
Steve Richardson 2000-07-06

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