I can't recall if this happens in any of the other series, but in Voyager I've noticed that lighting on the bridge (and, perhaps, other parts of the ship as well) dims whenever Red Alert is called. Why is this?

Common sense would dictate that low light conditions are a safety hazard as well as an eye strain. Sure, this may be somewhat acceptable when you want the ship to simulate a day/night cycle for the sake of crew comfort (as I can recall seeing once or twice in TNG). However, I do not think it would be sensible for this to be the chosen configuration during times when the crew needs to be functioning at peak efficiency.

If anything, I would expect that the ship's interior should be switched to maximum comfortable illumination levels during Red Alert - not minimal. I expect the out-of-universe explanation is that this is for dramatic effect, but is this otherwise justified or justifiable from an in-universe perspective?

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    The Enterprise uses incandescent light bulbs. As such, nearly 78% of the power budget goes to lighting the bridge. Obviously during battle this is unacceptable, so they have an ensign in the back room use a vintage 1970s rotary dimmer dial to knock that down a bit, giving Federation ships a distinct advantage in a fight. – John O Dec 5 '12 at 16:07
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    Except that I don't think the bridge dimmed on any of the Enterprises during red alert. Maybe Ent-C in Yesterday's Enterprise, but they had had a lot of damage to begin with. – Xantec Dec 5 '12 at 16:32

The dimming of the Bridge serves several purposes, in and out of the context of the show. Dimming the lights, in context, means people are likely focused on their own displays, resolving whatever the demands of their jobs are. Out of context, this makes it clear to the viewer, this is a time of tension and should be watched closely.

However strange it may seem to the non-military person, there is some precedence in the real Earth military, particularly in the Navy. I will make comparisons to the real Earth's military as a way of explaining this.

  • In the Navy, 90% of the crew can navigate a ship in complete darkness. We are trained to do this because a loss of power or damaged sections of the ship may leave us without even emergency lighting. That last 10% are the new guys who may have just signed on to that ship and are still learning their way around. During an emergency, those less experienced members would always be teamed up with far more experienced crewmen

  • Ships in the Navy turn down their lighting at sea and during combat operations to make their ships less visible and thus less easily targeted. Onboard interstellar craft, I suspect less power usage is better, reducing radiation signatures. Given the amount of energy their ships are in the habit of using, and the sensitivity of the sensors of the era, it may be a moot point. Since we are not given a lot of information about how sensors function, any energy output reduction may be significant.

  • Onboard naval ships, some regions of the ship become brighter or darker depending on what they are doing. The Quartermaster's sections of the ship, where navigation and mapping may become brighter to better view their charts, but the CIC (Combat Information Center) turns out its lights to better view its combat plotters, radar display screens and electronic warfare displays. Lighting becomes very localized in those regions applying light only where needed.

Combat Information Center of the USS Thomas S. Gates (CG 51)

Combat Information Center of the USS Thomas S. Gates (CG 51)

  • On Federation ships, I suspect a similar protocol is being enacted. Reducing lighting onboard the bridge may focus attention on whichever display or service you are in control of. I agree LCARS (Library Computer Access/Retrieval System) appears to be a difficult to navigate command and control system, but I suspect it is more intelligent presenting very specific commands in an easy to follow fashion. Since the computers can be accessed by voice, sub-vocalizations may make it easier to navigate LCARS.

LCARS Diagnostic Display of a Starship

LCARS Diagnostic Display of a Starship

  • Lastly, a ship might dim its lighting under combat operations as power system are damaged under attack. When primary ship's light goes offline, some ships have localized power to keep lighting services available for a limited time, able to be controlled at a local site. This emergency lighting may allow for evacuations, moving of weapons, resources, or injured crewmen.
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    I can DEFINITELY speak to the dimming of lights to make reading consoles easier. At my office, I have 4 monitors on my computer. It is most definitely easier to read all my screens when the lights in the room are out than not. This is especially true when it is dark out, little to no natural light, like one would generally have on a starship. – eidylon Dec 5 '12 at 17:46
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    As an aside, I agree LCARS ... appears to be a difficult to navigate command and control system, but I suspect it is more intelligent presenting very specific commands in an easy to follow fashion - The LCARS interface can be easily reprogrammed by each user to create a customized UI that's easy for them to use, without sacrificing functionality. This is said through dialogue rather than shown onscreen because it's one of the Holy Grails of UX that we have yet to crack IRL. IIRC, Tom Paris had an unconventional configuration for Navigation, for example. – Izkata Dec 5 '12 at 19:00
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    @Izkata We aren't that far away IRL. On any multi-user system the layout of icons, widgets, live-tiles etc, in addition to interface coloring and background images can all be customized (policy permitting) to suit each user's preferences. And while there are obvious differences, the Windows 8 start screen actually reminds me of LCARS a lot. – Xantec Dec 5 '12 at 19:11
  • @Xantec Well, true, we are much closer now. But back when these aired, certainly not, and we really haven't gotten very close to what's been shown in Trek, soo... =P – Izkata Dec 5 '12 at 20:09
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    If the power did completely go out, going from dim to nothing would be better than going from bright to nothing for people's eye adjustment. Just a thought. :) – Gordon Gustafson Dec 5 '12 at 21:33

On submarines, going to battle stations ("red alert") involves switching from the normal white floods to blue floods. This goes way back to the very first submarines, which had deck guns and did most of their fighting while surfaced. The blue lights were used when preparing to surface at night, to acclimate and preserve the crew's night vision. The human eye can distinguish shades of blue relatively well compared to other colors (or even white light), and to our brains, blue = night, so a blue light can be dimmer while still providing the appropriate lux level to function (displays that must be read while under these conditions are backlit), and not causing pupils to contract. That allowed the deck personnel to transition from inside to outside easily.

On most shows that draw from this notion of battle stations, including Star Trek, they try to follow the spirit of this changeover, but the same properties that make blue light great for night vision make it terrible for filming; film and camera lenses don't have the same dynamic level humans eyes do, and most of them were designed for white-light exposure. In addition, "red alert" triggering a blue light is counterintuitive. Finally, most skin tones look terrible under blue light.

So, the lights are instead simply dimmed. In TNG they adopted the dim lights about halfway through the series, usually with a delayed dim; a call for Red Alert doesn't immediately dim the lights but as they cut away and then back into the bridge you'll notice the lights have dimmed. In-universe this would have much the same effect as a blue light. Out-of-universe it allows easier filming (just reduce aperture or decrease film ISO speed) and also provides a dramatic tension; dark is intimate, drawing you into the scene, and also mysterious and suspenseful; you know something's going to happen when it's dark.

  • +1 I was totally thinking a mixture of "submarines" and "getting in or getting out of the vehicle". IIRC commercial aircrafts do the same on departures and landings (when a crash is unconfortably likely to happen) at night, when having your night vision engaged might help escaping faster – ZJR Dec 5 '12 at 23:54
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    Blue light = night? Are you sure you don't have that confused with red light? f.lux has research that indicates that blue light reminds of us daylight, and increases levels of cortisol (which reduces melatonin). And I've always read that red light is the frequency that preserves night-vision. – John C Dec 7 '12 at 0:23
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    For better or worse, red light has been typically used in aircraft cockpits to present information while attempting to maintain good night vision when looking outside the cockpit. Oddly, car dashboards use green light, despite having exactly the same considerations with respect to the driver's vision. At any rate, dimming the interior and instrument lights would serve to improve vision when it's necessary to take a look outside. – Anthony X Aug 4 '14 at 2:11

The explanation is put somewhere that this is to allow the crew to focus more on the panels (themselves emitting light) than be distracted by ambient lighting.

This does seem unreasonable though as the flashing red lights everywhere are likely quite a distraction and that LCARS's heavy-text based panels are hardly a good UI for use in a stressful circumstance.


Two possibilities in addition to Smalltown2k's answer, that aren't necessarily mutually exclusive, come to mind.

Due to the circumstance of being lost in unknown parts of the galaxy, Janeway may have instituted certain power saving directives. During a time of high alert specific systems might be deactivated or placed into a reduced power mode so that power reserves and/or auxiliary power reactors do not need to be used unless necessary for the resolution of the crisis. This would allow the crew to stretch fuel and supplies as long as possible due to the unknown frequency of being able to resupply.

Alternatively, the Intrepid class starship may be somewhat underpowered. In this case it might be a necessity to reduce power to unnecessary systems during emergencies so that all tactical systems can be fully activated.

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    Interesting ideas, but if you watch DS9 you'll see that this happens on the Defiant as well, a ship that no one would call underpowered! – Mason Wheeler Dec 5 '12 at 17:20
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    @MasonWheeler Defiant and Voyager were different class of ships designed for very different purposes. A best practice on Defiant may not make sense on Voyager and visa versa, even if the end result is the same. i.e. the reason lights dim on Defiant may be different than why they would on Voyager. For example, when Voyager is in condition blue (landing on a planet) the lights still dim, even though it is not in red alert. This suggests limited power to me, but that might be my own preference. – Xantec Dec 5 '12 at 17:37
  • On power saving: I believe lights were kept dimmed when Voyager was attempting to traverse the void between the arms of our galaxy's.. So lights apparently do drain a high enough percentage of power (relative to engines + life support in this case) that it becomes worthwhile to dim them to save some power – Izkata Dec 5 '12 at 19:03

Having many astronomer friends, I know that red lights are better than blue lights at preserving night vision (sorry Navy guys).

However, the real reason it was done was due to the era that ST:TOS was filmed. In the sixties, everyone was use to WWII movies and that's the way they did it in the WWII movies. It was a meta way of letting the audience know that the actions was starting and to create the "going into battle" tension.


I always thought the reasoning is that if the power/lights were damaged, you would have better low light vision than if you were in a fully lit room.

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