Mike Lights, Inc. 

Primary Colors

Of all variables in stage lighting, color is probably the most difficult to control.  There is no problem in coloring a single beam, but difficulties arise in predicting the total additive effect of mixing several colored beams together.  Light mixing works rather differently from paint mixing.  Mix assorted paint pigments together and you will gradually move towards black.  Mix the three primaries together and you will actually get black.  However, if you mix assorted light beams together, you will move towards white.  And, if you add the lighting primaries together, you will get white light.

This is additive color mixing of light.  On the other hand, the mixing of filters rather than  resultant light, works in a subtractive way.  Mixing assorted filters in front of one beam will move its light towards black.  White light is a mixture of all colors in the spectrum.  By passing this white light through a filter, we are not coloring the light, but we are filtering out the other colors.  White light can be split into three primary colors:  red, blue and green. They can therefore be mixed together to make white light.  A deep red filter will remove everything except the red part of the spectrum.  Mix two primary colors and you will get a third color, mix other two of those primaries and you will get another color.  Mix those two resultants and you once again get a different color.  From here you´ll find information on how to mix Lee color filters to get white light.