Try walking in the dark with a regular white light then turn it off and see how well you can see and how long it takes for your eyes to adjust to the darkness. It takes awhile for your night vision to come back. Then try the same thing with a green or red light. When you turn off the green or red light, you will be able to see much better in the dark right away. I prefer red for deer hunting simply because deer do not see the color red. That doesn't mean deer can't see movement, or can not see you, they might even be able to see the light in a different manner than we do but if I turn the red light off, I can still see fairly well. For a long time I hunted private land and the rule was when hunting with others, we never recovered dead deer til after dark. We didn't want people wandering around the woods tracking deer while others were trying to hunt. There were times we needed white light to find blood and tracks. Getting in the woods in the morning or getting out at evening we always used the red or green lights or no lights.