Why are red lights used in darkened control rooms and other low-light situations?

[Apophenia]

In response to report: http://www.straightdope.com/mailbag/mredlight.html

I am not calling into question the report’s accuracy, but it bears mentioning that in relative recent history, submarines in the U.S. have switched from using red light to using blue lights, as red lights were found to have negative effects on the crewmen’s eyes after extended periods. One wonders whether it was the lack of long visual range in a cramped submarine that perhaps engendered nearsightedness, and why they chose blue since its energy is among the highest of visible colors, but the issue remains.

This is hearsay, largely: I, as a Boy Scout, stayed overnight on a decommissioned submarine in Michigan (whose name escapes me, to my shame) which employed the replacement blue lights with the aforementioned reason cited by those who maintain the submarine as a sort of historical artifact.

[Lust4Life]

@Apophenia

In response to report: http://www.straightdope.com/mailbag/mredlight.html

I am not calling into question the report’s accuracy, but it bears mentioning that in relative recent history, submarines in the U.S. have switched from using red light to using blue lights, as red lights were found to have negative effects on the crewmen’s eyes after extended periods. .
.

In my experience the red lighting was only used at night mostly so that peoples night vision wasnt too drasticly affected when they went outside though I expect that it didnt show up so much at a distance was also a factor.

They used to have red lighting(apart from the “red on”) inside C130 aircraft after dark when some genius decided that when the hatch opened for parachutists the glow could be seen from the ground so they got rid of it.

In a Hercules jam packed with squaddies loaded to the gills with weapons and equipment waiting to jump into the darkness it would have been comical if it hadnt been so serious.

We were all blundering round like drunken elephants and frequently falling over BEFORE the driver went into his low level tactical approach ,or pretending he was still a jet jockey according to your level of cyniciscim.
I bet the bloke whos idea it was got promoted to the upper echelons in no time at all.

[robby]

As of 2002, when I left active duty from the U.S. sub force, red lights were still used at night for the reasons noted in the report. Note that under normal operating conditions, normal white lights are used.

Anyway, I commented on this report last June when it first came out here:

@robby

…The reply didn’t address this aspect of the question, but actual submarine control rooms really are either “rigged for red” for at least 30 minutes prior to ascending to periscope depth at night, or the Officer of the Deck (OOD) wears wraparound red “sunglasses” to accomplish the same thing. Prior to beginning the ascent, the control room is “rigged for black,” and the only illumination in the room comes from low-intensity red light from the various gages, controls, and indicators in the room. This is to further assist the OOD in seeing out the periscope, and also prevents light from the control room from being visible at the surface through the periscope optics.

The new Virginia-class subs have non-optical electronic periscopes, I understand, so this may change in the future.

P.S. The lights on my 1992 BMW 325is, BTW, were more orange than red.

[Mr.Moto]

As always, it depends.

I spent an awful lot of time in a Combat Information Center aboard Navy cruisers and destroyers, and low-level blue lights were used there, since they reduced glare significantly on scopes and displays and also ensured that brightness settings could be set low on them to reduce screen burn and see more contacts.

At night in the passageways and many other spaces red lights were used so as not to interfere with night vision. The bridge was kept as dark as possible.