Why is zoomed-in text red and blue?

If we want to draw something on a computer screen, we do it by setting the colors of individual pixels:

This is pretty useful, but it isn't great if we want to draw something like this:

We can only set each pixel to one color, so in reality we might choose to set the pixels like this:

That's... not ideal. The boxiness of the pixel grid really cramps our style. Fortunately, there's a fact that helps us improve the situation.

When screen manufacturers create LCD screens, each pixel they make is built using three lights: a red, a green, and a blue. The lights are too small for your eye to distinguish, so the three primary colors blend together. When we set the color of a pixel, these three lights turn on or off accordingly.

Since we know the arrangement of the little lights (the "subpixels"), we can fill in just half a pixel by giving it a funky color:

Rendering half-pixels allows us to draw much more smoothly. In practice, this effect is most obvious when you zoom in on well-rendered text:

Pretty cool!