Courtesy of Rhett Allain

But what about the colors from a video projector? It essentially does the same thing. However, instead of a bunch 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 shoot out black light? Black light would be the absence of any light, as we saw before. How do you project nothing? First, let’s consider a screen like a TV. If you have three tiny lights (red, green, blue), you can make a tiny black dot by just turning off the lights for all three colors in that spot. Boom, it’s black!

So, is it possible that you just turn off the projector to make black? That can’t be right, can it? If that was the case, you couldn’t tell the difference between a projected black color and the screen without the projector even on. Yes, that is exactly how it works.

Check it out: In the following image, I’m projecting a slide that is half black and half white. The slide takes up most of the screen.