NTSC Color Television works by including a signal called the Color
Carrier (or subcarrier) along with the black and white picture.
You can see this signal clearly if you're watching any analog color TV show
on a black and white TV or monitor.
The top picture in each case is a highly colored scene with the left split
processed to black and white. The next views show the actual color carrier
in the television signal. Color TVs know how to turn this screen door pattern
into colors and then delete it.
The quantity of pattern determines how much color (Saturation). The microscopic
position of the dots on the screen tells the system which color (Hue).
It's this positioning trickiness that sometimes gives NTSC the green and
NTSC will not tolerate a colored object smaller than one or two dots, which is one of the
things that kills tiny red titles.