Research has shown that green light (approx. 540 nm) is effective in skin conditions involving redness, swelling, and other effects related to pigmentation.
Reference: Sorbellini E, Rucco M, Rinaldi F. Photodynamic and photobiological effects of light-emitting diode (LED) therapy in dermatological disease: an update. Lasers Med Sci. 2018;33(7):1431‐1439.