system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is T.V. static black and white fuzz instead of just a solid color?
gpt
Analog TV signals were originally black-and-white, so both the "snow" and the picture were all black-and-white. When color became available, a color signal was added to the transmission both in the visible picture shown on the screen, and also with a short hidden "burst" of color at the beginning of each line to ensure that the colors are in synchronization and correct. 

Color TVs detect this synchronization signal. If it isn't present, the color circuits are turned off by a "color killer" circuit. Otherwise a weak black-and-white transmission would have colored "snow", nicknamed "confetti" in the industry. This would be very distracting and make for unpleasant viewing of black-and-white broadcasts on a color TV. 

When you tune to a channel with no signal, random noise is amplified and appears as dots on the screen. Because there is no color sync signal in the random noise, the TV turns off the color circuitry and you see black-and-white "snow". A weak analog color signal will have confetti in color, but if it's just random noise with no signal at all the color circuits are disabled.

Modern digital TV signals use a totally different process and if there's no signal present the TV set itself puts up an error screen or simply goes black.