radipano: Kada pomesate sve svetlosti razlicitih boja, dobijete belu svetlost,
a kada pomesate boje koje su materijalne prirode dobijate crnu boju. Mozda nisam najjasnije objasnio ali eto.

JankoNIS: To je normalno. Svetlost je mesavina svih boja iz vidljivog dela spektra (sve boje u dugi). Zato je prizma razlaze na pojedinacne boje.
Materijalne boje (kako si ih ti nazvao) se mesaju obrnuto, tj tako da zbir svih boja daje, teorijski, crnu. Zato sto su materijalne boje sastavljene od pigmenta, tj cestica.

Mala napomena, bela i crna u materijalnom smislu nisu boje. Bela je odsustvo boje a crna je skup svih boja. One su boje samo u gradjevini.

P.S. Veceras su mi objasnjenja malo konfuzna. Nestalo mi je KokaKole. :)

Additive and subtractive colors
There are two ways to combine colors: additive and subtractive.

A TV works by additive colors: you put a red, green, and blue light and it appears white.

A crayon works by subtractive colors. A red crayon absorbs blue and green light. A green crayon absorbs blue and red light. And so on. Put all three together, and any photon hitting the surface will be absorbed by one of the three.

We usually define color in terms of what we see (what’s reflected or emitted) rather than what’s absorbed. If you want to say that a red crayon is "really" blue+green, because it’s hoarding all of those blue and green photons... well, I guess that’s one way of looking at it. But it’s really turning those blue and green photons and converting them into heat. They’re not being saved up to be emitted as blue and green later.

So we say that "black" is when no photons are reaching your eye, and a "black" surface is one that absorbs all of the photons so that none hit your eye. And space is black because there’s nothing out there putting out photons (except where the stars are).

Actually, it’s an important observation that the sky is black. (I’m digressing here.) Scientists call it the Olbers Paradox. If space is infinite, then every point in the sky must eventually point to a star. So why isn’t the sky white? It means that the universe can’t be infinitely big, or infinitely old. The night sky proves that the universe

milekinez: Ma malke drugacije belo telo reflektuje ajde 100% svetlosti tj ponasa se kao ogledalo

Shadowed: Meni nikad nije uspelo da koristim beli papir umesto ogledala.

bakara: a meni nikad nije uspelo da dobijem crnu kada pomesam sve tempere :)