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I had heard that you can save power by using a black background instead of a coloured background. Is there any evidence that this saves power on people's monitors?

Is this a way that we can cut down on energy consumption (millions of users times milliwatts add up over time). It could also affect battery life on mobile devices.

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migrated from Apr 28 '10 at 5:24

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Make the text and images black as well, this will save energy because people won't visit your site more than once :) – Lasse V. Karlsen Apr 28 '10 at 5:16
@Lasse i think powering down the web server saves even more energy. – icelava Apr 28 '10 at 6:48
and flipping all electronic devices in your house/work saves even more $$ and money! – studiohack Apr 29 '10 at 2:39
up vote 14 down vote accepted

No, it doesn't save power.

You can save power by turning down the brightness of your screen, or (obviously) by turning it off when you're not using it.

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Incomplete answer - it depends on the display technology. You answer is correct for the type most commonly used today (LCD screens with CFL backlight). – sleske Jul 22 '11 at 8:52
@sleske According to this test black screens will reduce energy on backlit LCD screens. – THelper Jan 30 '13 at 15:36

You would expect a black background to save power on a purely emissive display such as actual LED (as opposed to LED-backlit LCD), OLED or plasma. CRT I'm not sure about because I don't know exactly how it dims the electron beam.

However, the most common type of computer monitor these days is LCD, which as others have pointed out, actually uses energy changing the LCD to absorbing mode to make pixels black.

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Yes, it can save power on the AMOLED screens used on Google's Nexus One, the HTC Incredible, and other mobile phones. Linky

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There is some power savings with a large CRT. I had a 19" CRT (now sitting in the bottom of a closet due to being replaced by a 22" widescreen LCD) hooked up to a UPS, and with the computer in an idle state showing a mostly black screen would have 2 of the 5 load indicator LEDs lit, but a partially white screen would bump it up to 3.

Now, could this be called "considerable"? Not likely. But it is more than none.

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protected by Nifle May 15 '12 at 21:21

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