Color Theory and Physics (Destiny)

by INSANEdrive, ಥ_ಥ | f(ಠ‿↼)z | ᕕ( ᐛ )ᕗ| ¯\_(ツ)_/¯, Tuesday, October 09, 2018, 15:25 (2214 days ago) @ Cody Miller

I never understood why TVs need calibration?

Why doesn't every digital color value have one and only one corresponding physical value in terms of light wavelength and intensity? So like, a YUV value of XYZ represents light with a wavelength of 480nm with an intensity of how many ever candela. Why don't the digital values have exact defined real world specs?

Can you elaborate?

A pixel sensor on a camera reads light of X nm and Y intensity.

Why can't the display then show light with X nm and Y intensity?

I know about gamma and shit, but even with that why are in and out not exactly the same?

Alright. I'm pulling out of my brains archives here, so... I can't guarantee total accuracy here. I think I can get out enough explanation for at least a push.

For starters, your examples as I interpret them, presume a world with zero entropy. That ever pesky 2nd law of thermodynamics, to say the least. Plus, there are the differences in the type of panel or screen, the array used, and the differences in how these elements are manufactured in a factory.

It does not matter what the signal is, if the elements used to display them can't or won't do it.

You ever wonder why there is a different color gamut for print, then there is for digital? If you didn't know then, I'll tell ya, CYMK is print and RGB is digital. Why? Well - it's based on how we see it. Print is refractive light, so "white" paper gets varying degrees of black ink mixed with colors. RGB is directly light based, light is being pushed straight into our eyeballs. The screens when off are black, and made white by our digital ink... light, which is then parsed into red, green, and blue respectively.

That is where color 'temperature' comes in. How "white" something is. That white value, when it drifts effects how ALL the colors appear. If the base light becomes too cool or too warm, well... even if the signal is pure it doesn't matter.

How does the white value drift? Full circle. Thermodynamics! Yay!

At least... that's what I recall. Take it or leave it. :P

One more thing, I have no idea if this applies to OLEDs as well, as those diodes are pure color, no back light needed. I guess in theory they could... but I don't know.