Additive Color Mixing - Projectors


Demonstrate additive color mixing of lights. ◙


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


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




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.


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).