Temperature describes a distribution of wavelengths. Higher is bluer, lower is yellower. Both brightness and color matters. If you want to be as safe as possibl

Temperature describes a distribution of wavelengths. Higher is bluer, lower is yellower. Both brightness and color matters. If you want to be as safe as possible, buy pure red LEDs for use 1-2 hours before bed and don't expose yourself to any non-red light. The difference is (no pun intended) night and day.