Using long wavelength light, such as red or amber light, in the middle of the night is less likely to reduce melatonin production unless it is very bright.

“The other is if you are going to use light, using long wavelength light, because, as you recall, these intrinsically photosensitive melanopsin cells within your retina that convey the signal about bright light in your environment to impact melatonin, to shut down melatonin, respond to short wavelengths of light. So red light is long wavelength light. You now understand that from our discussion about the physics of light. And if you were to use amber-colored light or red light and even better, dim amber or dim red light in the middle of the night, well, then you would probably not reduce melatonin at all unless those red lights and amber lights are very, very bright.”

“I have the red bulbs on because it's nighttime and I don't want to affect my normal melatonin production so at night I just hang out on the red lights”