“This was strongly established by photographer John Ott. And the Ott light bulbs are still regarded as the best available full spectrum lighting.”
Yes, the red part of the spectrum is the healthiest, that’s why incandescent bulbs are the best light from a health perspective.
Blue light is the one with most ability to mess up the sleep cycle, another reason why incandescent bulbs are the best.
Computer screens are also implicated for sleep issues.