You are, but all that means is that you anti-GC the desired color if you've chosen it by color picking based on what you see in the color chip. Since most people don't have a desired color, but rather they just eye-ball a test render, it's not that important. For example, if you're trying to get a nice orange firelight glow from a light, you choose an orange, see that it doesn't do what you want, and you choose a richer shade. In effect, this is manual anti-GC.

If, however, you wanted precisely 100% red and 50% green, to make a rich orange without even bothering to look at how it renders, then the color you want is RGB 255, 128, 0, by definition. Those are the linear numbers for a 100% red and 50% green. 

---

Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)