CRT Monitors = RGB, Primary Colours = RBY

kjf

kjf

Likes Bikes and Dirt
The primary colours are red, blue and yellow. (At least that's what I've been taught to believe).
No other colours can be mixed to make these 3 colours.

So that got me thinking, why do CRT monitors/TVs have red, green and blue?
I looked up 'primary colours' on google, came up with RGB, and on some of the diagrams, it showed that red + green = yellow.

Ha, like bloody hell it does. I just tried it then with paint, mmm, anyone up for some chocolate brown?

How do we get yellow, if the colours are red, green, and blue?
I have a bit of an idea as to how these things operate, but I'm still puzzled.

Anyone?
 
S.

S.

ex offender
It's because colours of paint as primary colours, and different wavelengths (colours) of light as primary colours differ. There is no yellow wavelength of light afaik, it's a combination of green light and red light. However if you mix green and red paint, you won't reflect green+red light.
 
alpinestar12

alpinestar12

Likes Bikes and Dirt
My Physics teacher told me the answer to this, but I didn't understand it totally. When you paint on paper, you are taking colours away, that is why when you mix more than 3 or 4 colours you always end up with brown or simmilar. But a computer screen is emitting light.

I dunno. I think this is along the lines of what he said.
 
S.

S.

ex offender
treggs said:
S, so what does the Y stand for in ROYGBIV? :p

EDIT: Tomas is on the money
Click to expand...
Aren't orange and yellow (as we perceive them) mixes of the R and the G wavelengths though? Though I guess that'd probably be a half-way point... :eek:
 
treggs

treggs

Treggs Tuned
S. said:
Aren't orange and yellow (as we perceive them) mixes of the R and the G wavelengths though? Though I guess that'd probably be a half-way point... :eek:
Click to expand...
Yes to make it in a CRT you would mix colours(as there are only three available) but the light spectrum is continuous(sp?). The visible light spectrum is from approx 400-700nm with yellow being around 560nm.
 
s73v30

s73v30

Likes Dirt
THere are 2 set s of primary colors

lights primary colors are G R B

Paint is different R B Y are the primary colors.

hard to explain but light mixes differently

Ill check my text tomorrow to confirm.

Whoa Yr11 Physics at its best.
 
scblack

scblack

Leucocholic
So how do we make yellow on a plasma screen? None of this old CRT screen dinosaur crap thanks.
 
LJohn

LJohn

Likes Dirt
There is no bloody mixture of wavelengths. Yellow light is one wavelength. Any specific colour is one wavelength (I know there is a spectrum where the light appears yellow or green or whatever, encompassing an infinite range of specific wavelengths, that's beside the point. I'm talking the one true pure yellow, if there is one). As far as I can understand, interacting two wavelengths causes interference producing another wavelength. Red and green produce yellow. blah blah blah.

Plasma screens work because they have a gas which produces green, red or blue when electrically excited, instead of shooting electrons down a tube. So they are thinner, but work on exactly the same principal.
 
treggs

treggs

Treggs Tuned
b_S said:
http://youtube.com/watch?v=PmJx9Slkoms

That laser only has a green and red diode, as mentioned the interference gives yellow. Spiffy :)
Click to expand...
Reach for the lasers :p

I have wondered if a low power RGB scanning laser could be used as a projector. I'm sure someone has invented it and it would have to be superior to the stupid bright lamp setup that is used these days.

No colour fade (that LCD projectors get) and no rainbow (that DLP's get).

Anyone played much with scanning lasers?
 
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