Additive Color Mixing - Projectors

Purpose

Demonstrate additive color mixing of lights. ◙

Equipment

Three slide projectors with intensity controller box on rolling stand with filters.◙

Suggestions

Use this demonstration as a way to introduce both positive (R,G,B) and negative (M,Y,C) colors.◙

Images

n3-02

Description

Three slide projectors in a special three-projector mount on a roll-around cart are equipped with color filters. The projectors have been re-wired so that the intensity is adjustable by changing the voltage on the bulb without affecting the fan. The colors are easily seen, and additive color mixing can be nicely shown: R+B=M, R+G=Y, B+G=C, M+G=W, Y+B=W, and C+R=W, where R=red, G=green, B=blue, M=magenta, Y=yellow, C=cyan, and W=white.

References

William A. Butler, Douglas Davis, and Charles E. Miller, Jr., Color Mixing for a Large Audience, TPT 17, 43, (1979). ◙R. D. Edge, String and Sticky Tape Experiments: Demonstrating Additive Primary Colors, TPT 22, 320-322, (1984).