Exploring the Color of Overlapping Spotlights

Question:

When you shine the red spotlight and the green spotlight on the feature presenter, with the beams of spotlight overlapping on the presenter, what color of spotlight is seen through the mixture of the two colors?

Answer:

When red and green spotlights overlap, they produce yellow light. This is due to the additive color theory, which applies when mixing different color lights and is distinct from subtractive color mixing used with pigments.

Explanation:

When you shine a red spotlight and a green spotlight on the feature presenter, with the beams of spotlight overlapping, the color seen through the mixture of the two colors is yellow. This phenomenon is explained by the additive color theory, which predicts outcomes when various color lights are mixed. Red light has a longer wavelength, around 660 nm, while green light has a wavelength near 530 nm. When combined, these wavelengths create the perception of yellow light.

On a white paper, which reflects all colors, the combination of red and green light also appears yellow. However, this is not to be confused with subtractive color mixing, which involves pigments and dyes. In subtractive mixing, such as when you mix different colored paints, mixing red and green would result in a different color because the pigments would absorb (subtract) some wavelengths of light.

In the context of the colored spotlights at a live event, utilizing the principles of additive color mixing is crucial for achieving the desired visual effects. This understanding allows operators to predict the results of overlapping different colored lights on stage.