On an laptop LCD screen does the color black use more energy than the color white?

Question

I don't know exactly how laptop screens work, but if a screen has to be backlit anyway, wouldn't any additional color need extra energy?

thanks for all of your expert opinions!

Answer 1

Most laptop screens are TN-film (because it is the cheapest of the TFT technologies and also uses the least power) and with TN-film the pixels are on when no power is applied to the transistors and off when power is applied.

That means that most laptop screens do use more power when displaying black (or as close to black as they can get) then they do when displaying white although the difference is pretty insignificant.

Although you should reduce the brightness of the backlight to as low as you can read the screen when on battery.

A few laptops have IPS or *VA screens which use more power displaying white than displaying black but those are very uncommon in laptops because of higher cost for the panel and higher power consumption of those technologies. IPS and VA are pretty much reserved for high end desktop monitors where the higher power consumption isn't an issue.

Answer 2

This is a great question! The answer is that black uses less, but not much.

The way a LCD works is just like a digital watch with indaglow. The watch has bits of space that are turned black, but in low light you can't tell which ones, so a light must be used so you can see the numbers. Here:

http://en.wikipedia.org/wiki/Liquid_crystal_display

Wikipedia has a great explanation of it. But basically your LCD screen has an image on most of the screen most of the time and the actual battery used to produce this image, either black or white, is tiny compared to the amount used to keep the backlight running. Just like holding the light button down on a watch will burn out it's battery much faster, having the light illuminate your screen runs the battery down.

Just like some other people said, turn down the brightness to increase you battery time and have your computer turn off your hard drive when it's not used for a few minutes. You can also turn off unnecessary devices (like the modem and wired network card if you are wireless or wireless if you are wired).

So, after that long-winded answer, I'll get to the response: I believe the white usually uses less energy because the technology used lets light pass through when there is no power to the pixel and requires power to keep light from passing through the pixel. I think you will find though that the difference is minor compared to changing the brightness on the screen.

Answer 3

Well, for myself, I'd like black better than white. But, for the less scratch noticeably, I'd have to say white! Because when you scratch a BLACK computer/laptop, a big GREY bright mark appears. So, therefore white is better. Also, take the feel of the paint color in consideration. If its a spray feel (little rock kinda feel, like mine) it shows marks very well. And I hate that. a SMOOTH glossy feel/color is best. Thanks, and good luck!!

Answer 4

The back lighting requires energy as does the liquid crystal display. The screen uses less energy when black.

Answer 5

If you can make the screen go darker or lighter then the darker the screen the more battery you save.