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Re: [Phys-l] Projecting Black



Thanks, Rick. I'm wondering, though, how that "black" is transferred to my
Smart Board. It is quite "white" when no projected light hits it. Ron

-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu
[mailto:phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of Rick Tarara
Sent: Tuesday, November 06, 2007 3:44 PM
To: Forum for Physics Educators
Subject: Re: [Phys-l] Projecting Black

I think--just looked carefully at a black spot on a computer screen--that it

is simply that black does not illuminate any of the red, green, or blue
pixels. On an LCD screen, none of the pixels are activated.

Rick

----- Original Message -----
From: "Ron Curtin" <ron.curtin@charlottecountryday.org>
To: "'Forum for Physics Educators'" <phys-l@carnot.physics.buffalo.edu>
Sent: Tuesday, November 06, 2007 3:35 PM
Subject: [Phys-l] Projecting Black



A student asked me a question that I couldn't answer. When I pick up the
black pen on my Smart Board, I can write with a really black color ---
much
blacker than the appearance of the screen with no illumination at all.
Where does the black come from? I can produce most all the other possible
colors with a combination of the primary colors of light, but if I add all
the colors of light together, it seems like I should get white, not black.
Any help?

_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l


_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l