Incandescent bulbs are much less efficient than other types of electric lighting; incandescent bulbs convert less than 5% of the energy they use into visible light, with standard light bulbs averaging about 2.2%. The remaining energy is converted into heat. The luminous efficacy of a typical incandescent bulb is 16 lumens per watt, compared with 60 lm/W for a compact fluorescent bulb or 150 lm/W for some white LED lamps.
And if you visit the other links in the page you will have (note that there are several values per type due technological advances and quality):
From this list you can see very good candidates:
- Fluorescent lamps (average light but very durable);
- Sodium vapour lamp (above average light and quite durable);
- And LED lamp (very high light and a bit less durable)
However, can you guess which bad property fluorescent and sodium vapour lamps have that LEDs don't have? They have a warmup time:
- Fluorescent lamps need some seconds of warmup only, but they need an external device (starters) in order to turn on, and that devices need much more maintentance that the lamp itself. Also, they need a "cooldown" time between each cycle otherwise they lose their long lifespan quickly.
- Sodium vapour lamps need almost 5 minutes of warmup, also they produce some heat.
Even more, both lamps are fragile and can be broken easily with an impact or quick movement from the ship itself.
LEDs lamps don't have these disadvantages. They neither have warm up nor cooldown time. Also, they aren't fragile. They are very small and produce a lot of light. Due to their size, you can store thousands of them together and they won't break.
Color - majority white. Then, other colours.
This is much more difficult to answer.
If you are talking about energy consumption:
It must be red.
If you are talking about psychology you could read this investigation of 134 pages... I won't do that so I've looked at other places.
I'm quite sure someone will disagree with this description about colours, but this was my best attempt searching over the internet:
- Red: Increase heart beating rate, blood pressure and breathing rate, muscular tension, excitation, and desire, even hunger. It can increase aggressive reactions and comfort.
- Orange: Increase recreation, mobility, vitality. Estimule breathing and relax. May increase hunger.
- Yellow: Increase happiness and mood. Increase sight, mental activity, creativity and metabolism. Too much yellow can anger people easily.
- Green: Its sedative and help to sleep calmly. Decrease blood pressure, beating heart rate and stress.
- Blue: Decrease impulsivity. Make you more calm, quiet, peaceful and help to wake up. Increase blood pressure, reduce hearting rate and body temperature, and give you a tonic effect. This colour could increase productivity in workplaces.
- Purple: Increase resistance on muscles and tissues. Decrease sadness and fear but its a melancholic colour (and ambiguous).
- White: Increase happiness, clarity and produce a cleanness feeling. Also, make places more widen and luminous but also cold and alone.
I would use the different colour for different kinds of rooms.
I would suggest as a "default" colour white because any colour (less white) always makes more difficult to see another colour. Also, spaceships are small, and white colour makes things widen and clean.
- For bedrooms, I would recommend green or blue, maybe a combination of both (furniture of a colour and lights of another one). EDIT: Orpheus on comment has said it seems that green and blue can difficult sleep because they are also morning colours, even they can produce cardiac problems. So I would recommend instead a colour like white because it doesn't help to sleep, but it makes your bedroom/quarter bigger and cleaner.
- For passages white, because makes everything bigger and clean.
- For maintenance, fixing or alert something white, because it makes sight very clear, and in an intense light it keeps anyone awake.
- For working stations blue and white because it's relaxing and keeps you awake. Maybe blue furniture/machines and white light, so you can see clearly.
- For night mode are several options:
- Faint warm orange colour, because even in low quantities you can see something and its resemble dawn on Earth, which psychologically induces calm and sleep.
- Dark red, because of an effect that I'll discuss below.
- For nocturnal shift: blue, because it keeps people calm and awake. The absence of blue produces sleep.
- For failure red because in any moment power (and lights) can shut down.
The Purkinje effect states that in a low amount of light, our eyes can't distinguish red easily, but blue and green, that is why in low-light environments we can't see bright red, only brights blue and green.
So in a low-light environment, the red light won't be bright nor annoy your eyes, so it'll be easier for your eyes to adapt to darkness. Higher clarity for us but lower stress for our eyes can be provided with red, even intense.
The insensitivity of rods to long-wavelength light has led to the use of red lights under certain special circumstances – for example, in the control rooms of submarines, in research laboratories, aircraft, or during naked-eye astronomy.
Under conditions where it is desirable to have both the photopic and scotopic systems active, red lights provide a solution. Submarines are well lit to facilitate the vision of the crew members working there, but the control room must be lit differently to allow crew members to read instrument panels yet remain dark adjusted. By using red lights, or wearing red goggles, the cones can receive enough light to provide photopic vision (namely the high-acuity vision required for reading). The rods are not saturated by the bright red light because they are not sensitive to long-wavelength light, so the crew members remain dark adapted. Similarly, airplane cockpits use red lights so pilots can read their instruments and maps while maintaining night vision to see outside the aircraft.
@Joe bloggs commented that lamps should be connected with the central system, so anyone, when they want, can modify the colour or intensity according to their taste. Light could be modified in the control room, using the control panels in each room, or simply with an app on your portable device. Obviously, LED lamps that are able to change their colour are more expensive than normal ones because they are made of 3 LEDs (red, blue and green) but I think the benefits are greater than the cost in this case.
Finally, @user71659 suggested in a comment that LEDs are vulnerable to radiation and high energy particle damage but I don't think it would be a problem because a crewed ship should already be shielded for radiation, otherwise people could get sick. Also, in the future maybe it could be possible to make more resistant LED technology.
Well, like I said it was quite probable that I would receive comments!