Courtesy of Rhett Allain
But what about the colors of a video projector? It essentially does the same thing. However, instead of a series of tiny RGB lights, it projects RGB colors to different locations on the screen.
Projecting the color black
Now we’re ready for the fun stuff. How does a video projector create black light? Black light would be the absence of any Light, as we saw before. How do you not project anything? First, let’s look at a screen like a television. If you have three small lights (red, green, blue), you can create a small black dot by simply turning off the lights for all three colors at that point. Boom, it’s black!
So is it possible that you just turn off the projector to produce black? That can’t be right, can it? If that were the case, you wouldn’t be able to tell the difference between a projected black color and the screen without the projector on. Yes, that’s exactly how it works.
Check it out: In the image below, I’m projecting a slide that’s half black and half white. The slide takes up most of the screen.