Is the Trichromatic Theory Correct?

So which is correct? It turns out that both of these theories are necessary to fully describe the intricacies of human color vision. The trichromatic theory helps to explain how each type of cone receptor detects different wavelengths in light.

Has trichromatic theory been discredited?

Opponent-process theory has largely been discredited. ... Both trichromatic and opponent-process theories have largely been discredited and replaced by newer ideas.

What does the trichromatic theory fail to explain?

Trichromatic Theory. While the trichromatic theory makes clear some of the processes involved in how we see color, it does not explain all aspects of color vision. The opponent process theory of color vision was developed by Ewald Hering, who noted that there are some color combinations that people simply never see.