A Brief History of Color Changers: Part 2
By Kevin Stone

In 1986, VariLite introduced a new system called Series 200 . This system debuted with a vastly improved control system and two new luminaires. The VL2 was a replacement for the original VariLite (VL1), but with many improvements, including a revamped color mechanism. This new mechanism used high-speed direct-drive stepper motors instead of servos. They were much quieter and did not require such precise calibration. Now there were only two wheels, each with 16 filter slots (15 filters + 1 open) allowing for 256 colors. The new filters were trapezoidal in shape and mounted at the narrow end, allowing them to fit edge to edge around the wheel and eliminating the annoying blackout problem. The filters were carefully selected to allow for the broadest possible range of usable colors. The second new luminaire, the VL3, was an incandescent wash fixture that used a new type of color system. It made use of another interesting property of dichroic filters. Dichroics lose efficiency as they rotate off axis from perpendicular to a light source. As they rotate from 90 degrees toward 180 degrees, they reflect less light, allowing progressively more to pass. The VL3 used three sets (one each of cyan, amber and magenta) of three rotating rectangular dichroic plates mounted side by side. When rotated edge to edge, the filters were perpendicular to the light source and at full efficiency, but each set could be rotated up to 90 degrees off axis to create any gradation up to open white. The combinations of these three sets at various rotations could create virtually any color obtainable by a par can/ gel combination. Best of all, the VL3 was capable of timed crossfades between colors. This color system continued virtually unaltered into the later arc-sourced VL4, and was modified from rectangular plates to a radially mounted arrangement for the VL5.

VariLite patents prevented other companies from using these exact color systems, but numerous other automated-function lighting systems, many of which eschewed the yoke mounted pan/tilt focus method in favor of moving mirrors, proliferated in the mid-1980s. Many simply utilized a single wheel of an assortment of up to a dozen dichroic colors. At least one, the Color Pro developed by Austin-based High End Systems, used three lamp sources in a single housing filtered by red, green, and blue fixed dichroics in an additive system. This luminaire suffered from the previously identified inherent problems of additive systems, but was nonetheless an important and popular unit for some time. Others achieved color crossfade capabilities by using graduated dichroic filters. VariLite’s VL7 uses a combination of two graduated dichroic plates, one covering the spectrum from red through indigo and another ranging from cyan through amber and magenta. Each plate is graduated by saturation along its other axis, and the two can be used singly or in combination. The cyan/amber/magenta plate allows access to colors that are the result of combinations of non-adjacent spectral colors. For range of available color, this may be the best system available today, the only drawback being the inherent inability of current crossfade-capable systems to create the type of instant color bumps attainable in some of the better wheel-mounted filter systems.

Today, it is safe to say that there is a color changer for almost every need and almost every budget. If recent history is any indicator, the few needs that are not met by the current technologies likely soon will be.