PDA

View Full Version : Blue TV Screen Illusion


frenzal_dude
Sep5-11, 10:39 PM
If the blue screen on your TV is only 1/3 blue, 2/3 black, why do we see it as blue?

(Each pixel on a Cathode Ray Tube TV is made up of 3 phosphor dots, red green and blue, so when you have a blue screen, only the blue dot is lit up).

Drakkith
Sep7-11, 06:54 PM
The blue pixels are the only ones that are giving off any light, so they are the only ones you can see. Black is merely the absence of light or color.

frenzal_dude
Oct12-11, 07:52 AM
The blue pixels are the only ones that are giving off any light, so they are the only ones you can see. Black is merely the absence of light or color.

True, but when the TV is turned off I can still see the dark screen just as much as I can see the blue screen when it's turned on.
So why if 2/3 of the screen is black, the screen still looks blue?

phinds
Oct12-11, 08:19 AM
True, but when the TV is turned off I can still see the dark screen just as much as I can see the blue screen when it's turned on.
So why if 2/3 of the screen is black, the screen still looks blue?

Get real close with a magnifying glass and you should see little blue dots. Since they are the only thing radiating (black is the ABSENCE of radiation) they are the only thing you see.

Monique
Oct12-11, 10:56 AM
It has to do with resolution, if you get close enough you can see the individual pixels. When you are too far away the blue and black pixels were merge and only the emitted light from the blue pixels will be seen. The black pixels still have an influence, since obviously the intensity of the light will be less than when all the pixels would have been blue.