I would like to set my desktop background on an LCD or LED monitor such that it consumes as little power as possible. Does the background color affect the power requirements? Does white use more power than black?
On a CRT I always assumed that black used the least power since it doesn’t have to fire the electrons at the screen. But LCD/LED monitors aren’t like that. From what I understand, there are dots that make color and the backlight lights them up. But the backlight is always on. So maybe white is the least power color in these cases? Or maybe a different color that represents the unpowered state of the dot? Anyone know?
To be clear, there aren’t really LED monitors being sold (beyond enormous displays such as billboards, stadium TVs, etc). Generally when people refer to LED monitors, they mean LCD with LED backlighting, as opposed to a cold cathode flourescent lamp (CCFL) backlight.
You are correct in that generally the backlight is always on, regardless of the color of the pixels being displayed, and the backlight is what consumes most of the power. This will only change if you’re talking about a local dimming display. These displays will turn off backlighting in areas that are displaying solid blacks, to make the blacks appear darker. This would also consume less power.
Differences between types of backlighting: TVs - CNET
As you said, the backlight is always on. And the backlight is what consumes most of the power. So the power consumption does not depend on what’s being displayed.
Although the backlight brightness can be controlled by the user. So another way to think about this is, the most energy-efficient color scheme is one that provides highest contrast, and allows you to read the display at the lowest brightness setting.
By the way, “LED display” usually refers to an LCD display with LED backlight (instead of cold-cathode fluorescent lamp). So the power consumption issue is the same as any other LCD. But OLED and AMOLED displays are completely different; they are made up of tiny little LEDs that can be controlled independently. So on these devices, a mostly black screen consumes the least power. Some have reported further improvement by using a red-on-black color scheme (i.e. black background, red characters).
Maybe so, but I’d bet you’ll end up spending more on optometry than you’d save in electricity. Just thinking about that color scheme gives me a headache.