# Thread: How to make yellow with RGBA color?

1. ## How to make yellow with RGBA color?

Hi! I try to make it with 1 green and 1 blue, but failed.
Can you tell me what propotian is good?
Thank you!

2. ## Re: How to make yellow with RGBA color?

G + B = Cyan
R + G = Yellow
R + B = Purple/Magenta

3. ## Re: How to make yellow with RGBA color?

i.e. ...

glColor3f(1,1,0);

4. ## Re: How to make yellow with RGBA color?

Oh, it is different from the common sense(Y=G+B).
Thank you!

5. ## Re: How to make yellow with RGBA color?

Actually, doesn't Y+B=G?

I'm colorblind (truth), so be gentle

In real life, not computer graphics. R+G=Y there.

[This message has been edited by Omaha (edited 07-26-2003).]

6. ## Re: How to make yellow with RGBA color?

How about take some blue and Red paint and mix them and see what you get.
Then again maybe I am thinking about dyes, but in paint your mixing with a white base in most cases. And in a dye you are mixing with a clear water base.

Anyway for openGL this is correct.

Red + Green = yellow

Red + Blue = magenta

Red + Blue + Green = white

Basic science class stuff

The then again there is not common about computer graphics and programming.

Originally posted by earth_walker:
Oh, it is different from the common sense(Y=G+B).
Thank you!

[This message has been edited by nexusone (edited 07-26-2003).]

7. ## Re: How to make yellow with RGBA color?

As far as I can remember, the problem here is that mixing colors is different with light and paints

I´m not sure, but I think OpenGl works in the "light way" no paint way.

I.E.
(light) glColor3f(1,1,1) = white
(paint) glColor3f(1,1,1) = black

[I know RGB are not the primary in paint, but is just an example ]

?

8. ## Re: How to make yellow with RGBA color?

Mixing paint to see how to call glColor is not going to work very well. Mixing paint is subtractive blending of the colors, and mixing light is additive blending.

So mixing red, green and blue paint should give you a pretty dark color.

9. ## Re: How to make yellow with RGBA color?

Gah. This is additive color mixing in a nutshell. This is what all video devices use:

Primary colors: red, green, blue
Secondary colors: magenta, yellow, cyan
Tertiary color: white

red+green = yellow
red+blue = magenta
green+blue = cyan
red+green+blue = white
no color = black

[This message has been edited by Tokage (edited 07-26-2003).]

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