Course: Science Subtest I
Lesson: Optics and Waves
Topic: How We See      Page 16 of 27  

When all the colors or wavelengths of visible light are present, they combine to give white light. Note that the rules for mixing colors are different for light and for paint. Mix red, green, and blue light, and you get white light. Mix red, green, and blue paint, and you get brown paint.

That's because paints and crayons do not absorb and reflect pure shades of color — there is always some mixture. See the difference between mixing light and mixing paint colors.

This site is a lesson plan for teachers on mixing light versus mixing pigment.

Colored lights shining on a white surface. The combination of red, green, and blue light gives white light. Red and green light make yellow. Blue and green light make cyan. Red and blue light form magenta.