First, you only need light for viewing, the snake doesn't need it.
I have red LEDs in the top of my snake's viv.
Here's what I know:
They can see red light, my snake reacts to my movement outside the viv when I'm lit by only the red light.
The red LEDs wash out my amel's colors, but we can see her without turning on the white overheads.
With the red lights on she acts the same at night as without them, cruising, drinking.
Red light does not affect human's ability to see, or adjust to seeing, in low light. When I was on a submarine we "rigged the control room for red " at night in case we had to go up. This was done so the officer in command could look out the periscope without waiting for his eyes to adjust to the lack of light.
Here's what I think:
Red light is less intrusive to the snake.
Red light is easier on the eyes for humans.
Your snake (and viv) look better in whiter light.