Red or Blue ?

[KriegsMarine]

Herr Kaleuns

I've noticed in some movies and some games （say uboat... etc） that the German uboats employ the Blue night lights in the control room and other compartments when being about to launch some night attacks - both surfaced or submerged （while the conning tower still uses the Red night lights）. In the meantime the USN submarins only use the Red night lighs as the standard night vision （all compartments and some Red goggles）. So in regard to historical accuracy which situation is authentic or both are okay ?

[Sailor Steve]

I had never heard of blue lights until I saw Das Boot. I haven't seen any reference sources that talk about it, So my guess would be red only. Then again, I could be wrong.

[ivanov.ruslan]

https://www.subsim.com/radioroom/showthread.php?t=239146 :Kaleun_Salute:

[UKönig]

I thought that blue light was used to signify silent running. Red light is used (even today) at night because it's harder to spot, say, from the air.
In a plane, looking down on the water for a surfaced uboat. Red light is used because it does not interfere with your night sight, and the colors red and green, to represent port and starboard, will still show up as red and green. Very important to tell them apart, in a life or death emergency...