Why is the "black" text on my Mac made up of so many different colors? My Mac has this nifty "zoom" function that kicks in when I hold control and scroll in and out.   If I zoom all the way in on black text on my screen, it is made up of many different colors.  Why is this?
The Mac is rendering text using subpixel resolution. See these explanations for instance:


Font smoothing, anti-aliasing, and sub-pixel rendering
Font smoothing explained