<p>Likely a gamma correction issue. Tertiary colours are some permutation of (1, 0.5, 0) in RGB, right? So the issue arises because without applying gamma, 0.5 appears less than half as bright as 1, so the blended colour skews towards the primary (1,0,0) rather than the secondary (1,1,0). The image below has linear colour on top, gamma corrected on the bottom, you can see the gamma corrected colours appear much closer to a halfway tone.</p>

<p><a href="https://i.sstatic.net/7wZsK.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/7wZsK.png" alt="enter image description here"></a></p>

CC BY-SA 3.0
2017-03-08T05:27:29.110Z
2017-03-08T05:27:29.110Z
russ
<p>I was suprised to learn that RGB tertiary colors are much more similar to RGB primary then secondary colors.
I was expecting they will be halfway between them and look more like this: <br/>
<a href="https://i.sstatic.net/M20cO.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/M20cO.png" alt="tertiary"></a></p>

<p>Rather then this: <br/>
<a href="https://i.sstatic.net/nigie.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/nigie.png" alt="tertiary RGB"></a></p>

<p>Is there a reason/purpose for this disproportion? <br/>
(I know how to calculate values- this is not my question. I'd like to know why correctly calculated tertiary RGB colors seems to be much closer to primary then secondary RGB colors)</p>

<color-science>
Why are RGB tertiary colors so similar to RGB primary colors?
user6187
# Why are RGB tertiary colors so similar to RGB primary colors?

(Asked by: username_0 on 2017-03-07)

I was suprised to learn that RGB tertiary colors are much more similar to RGB primary then secondary colors.
I was expecting they will be halfway between them and look more like this:   
[![tertiary](https://i.sstatic.net/M20cO.png)](https://i.sstatic.net/M20cO.png)

Rather then this:   
[![tertiary RGB](https://i.sstatic.net/nigie.png)](https://i.sstatic.net/nigie.png)

Is there a reason/purpose for this disproportion?   
(I know how to calculate values- this is not my question. I'd like to know why correctly calculated tertiary RGB colors seems to be much closer to primary then secondary RGB colors)

**Tags:** color-science


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## 1 answers

### Answer by username_1 on 2017-03-08. Score: 4

Likely a gamma correction issue. Tertiary colours are some permutation of (1, 0.5, 0) in RGB, right? So the issue arises because without applying gamma, 0.5 appears less than half as bright as 1, so the blended colour skews towards the primary (1,0,0) rather than the secondary (1,1,0). The image below has linear colour on top, gamma corrected on the bottom, you can see the gamma corrected colours appear much closer to a halfway tone.

[![enter image description here](https://i.sstatic.net/7wZsK.png)](https://i.sstatic.net/7wZsK.png)


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