Amiga.org

Coffee House => Coffee House Boards => CH / Science and Technology => Topic started by: elendil on October 02, 2004, 03:50:09 PM

Title: RGB colours - red green blue?
Post by: elendil on October 02, 2004, 03:50:09 PM

Hi.

We computerpeople all know that the primary(?) colours are Red, Green and Blue, and all other colours can be made from those.

But my gf here insists that in real life these colours would be Red, Blue and Yellow.

So what is it? And if she's right, why isn't it so in our computer world?

Sincerely,

-Kenneth Straarup.

Title: Re: RGB colours - red green blue?
Post by: Karlos on October 02, 2004, 03:55:45 PM

You are both correct.

When mixing light sources directly, R G B are your primary colours from which the impression of any other can be synthesised. This is best described as an "additive" process.

When dealing with natural, reflected light, the colour is actually determined by which parts of the overall spectrum are absorbed by the surface you are looking at. A red surface effectively absorbs all non-red parts of the visible spectrum and reflects only the red. This is best described as a "subtractive" process. It so happens that you can simulate any colour subtractively by mixing red, yellow and blue pigments.

Title: Re: RGB colours - red green blue?
Post by: Speelgoedmannetje on October 03, 2004, 04:10:50 AM

In short:
Red Green Blue are the primary colors for emitting light
Red Yellow Blue are the primary colors for absorbing light

Title: Re: RGB colours - red green blue?
Post by: Wain on October 03, 2004, 03:42:57 PM

Technically speaking, the primary colors of pigment are Magenta, Yellow, and Cyan(which are the secondary colors of light)...NOT Red, Yellow, and Blue -- You've heard of or seen CMYK listed on color printer ink cartridges? or possibly on a photo program? that's what they're talking about...Cyan, Magenta, Yellow, and Kohl(black).

Title: Re: RGB colours - red green blue?
Post by: whabang on October 04, 2004, 11:38:23 AM

Actually, K is for 'Key', IIRC.

Title: Re: RGB colours - red green blue?
Post by: bloodline on October 04, 2004, 12:59:44 PM

Quote

whabang wrote:
Actually, K is for 'Key', IIRC.

Sesseme Street!!!

Title: Re: RGB colours - red green blue?
Post by: redrumloa on October 04, 2004, 03:42:11 PM

Hmm I misread KGB instead of RBG  :-o

Title: Re: RGB colours - red green blue?
Post by: bloodline on October 04, 2004, 04:30:11 PM

Quote

redrumloa wrote:
Hmm I misread KGB instead of RBG  :-o

Those Damn lefties infiltrating your brain... to the right thing and shoot them out of your head!!! :crazy:

Title: Re: RGB colours - red green blue?
Post by: odin on October 05, 2004, 01:05:05 AM

:roflmao:
At last we found a good reason for private gun-ownership :-P.

Title: Re: RGB colours - red green blue?
Post by: iamaboringperson on October 05, 2004, 01:52:28 AM

With light, it's RED, GREEN, and BLUE. That includes monitors, video projectors, and computers (gfx card hardware, I mean).

Back in primary/elementry school, you probably mixed red, yellow, and blue paint together (along with white and black and brown, to try and make the 'yuckiest' looking color possible)

With print (magazines, etc.) the colors are Cyan, Magenta, Yellow, and Black (K). Black is only required, because CMY looks crap (not dark enough) on its own.

I hope that helps a bit.

Title: Re: RGB colours - red green blue?
Post by: asian1 on October 05, 2004, 05:03:49 AM

>Colors

Hello
Is there any professional color separation and DTP software for Amiga Platform? Is it compatible with Pantone color standard?

Is it possible to use Amiga1 or Pegasos for professional DTP?
Is there any driver for HP scanner, HP color laser printer etc?

Or is it better to run MacOnLinux + Apple OSX + Mac DTP apps?
Thank's.

Title: Re: RGB colours - red green blue?
Post by: bloodline on October 05, 2004, 08:01:45 AM

Quote

Or is it better to run MacOnLinux + Apple OSX + Mac DTP apps?

Yes.