Which background image uses more power on Windows Phone 8?

There are times that reading a blog post from Microsoft that's meant for a specific technical or developer audience can be confusing to the layman. Today, Microsoft posted up a new entry on its Windows Phone app developer blog that gives app creators some tips on how to make their apps use battery power more efficiently.

The blog post gives an example of how an app with the simple switch of a background images can actually save energy. It shows two different backgrounds, one lighter and one darker but each with the same kind of design and art textures.

Running an app with each background image for five seconds yielded very different battery power results. The purple background used 0.37mAh, which means that an app with the purple background can run for about seven hours on a Windows Phone device. However, the app running the black background used up just 0.09mAh, which means the app could run just over 24 hours.

The lesson? Creating an app with a darker background will use less energy. That is, of course, a good thing.

The blog also goes over how apps that connect to different wireless signals use different amounts of energy. In general, cellular connections use more energy than WiFi connections. App developers can also optimize their software to better use the CPU in the phone's hardware; for example, using animated pictures for an app will use more power due to the CPU processing the animations.

Developers can use Microsoft's Power Monitoring tool that's included in the Windows Phone 8 SDK to check on how an app consumes battery power. Microsoft says, "This tool can allow you to estimate (based on power modeling with a standard 1500mAh battery) the battery charge consumed by your app's use of CPU, display, network, and other resources, allowing you to fix energy bugs easily."

Source: Microsoft | Image via Microsoft

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The problem with this article depends on whxt type of screens you are talking about. BLACK is not a color...it never has been and never will be. Colors are created by different intensities of light. RGB (RED GREEN BLUE) are the colors that make up light. Without them, everything would be black.

LCD screens of ANY KIND imitate black, but are not true blacks. In those cases, and LCD produce a black that requires power, though it is lower than it uses to producc brighter colors.

LED/OLED/AMOLED don't produce any blacks at all. The screen is naturally black because color is produced by the electronics in the screen. Any color requires power. The brighter the color, the more power required. Black is cold, thus requiring no power at all in these screens types which is why colors look sharper compared to LCD.

Nokias clear black screens have nothing to do with black at all. Those screens are OLED based an are naturally black. What Nokia adds is a layer to help with light reflection so artificial/natural surrounding light, doesn't wash out the black.

Because LCD's are backlite, they can never produce a nIatural black...it is impossible. If you look at them, with no wallpaper and the screen is on, you will see that black is not dark, but has a little intensity. You can see this on the HTC Surround very well. It makes the screen look like it has a blueish hue. This is cause by the backlight. LED screens are not backlighted at all, causing a natural cold black. No phone screen out their so far can beat it.

When it comes to any image moving or stationary, if you use an LCD...any black you see is a reproduction/imitation. It is not true black. It can't be. Just take any iPhone and place it next to a Galaxy S II/III or Galaxy Note I/II and place themside by side and you will see the iPhone screen has a hue. All LCD's do.

Some phones produce what is called a natural white. It is the opposite of the AMOLED. Since the bulb produces whites, the electronics dont use imitation white which requires more energy. When color needs to be displayed, color simply appears in place of the white. This is a cold white where battery power is only used for the bulb in the panel...not the white on the screen.

Look at this video...http://www.youtube.com/watch?v=qaEk6WkZgKc it will show you the cold white I speak of. Basically u take a phone and put the brightness to its highest level. The whiter the better for brighter images. While darker screens produce better images that are dark.

The reason RED, GREEN, BLUES look so sharp on AMOLED screens, is there is no white light in the background cauing color wash. This is why you cant see many LCD based phones in direct light. The direct light is bouncing off the backlight and it washes out the color. AMOLED screens absorb light becaus eit cant reflect it because black can't reflect light. That is why black cars are hotter in hot weather vs bright colored cars bec black absorbs, while yellows reflect light/heat.

Most phone makers that use LCD's try to combat the issue with special coatings. But they will never work.The reason is the LCD panels natural to bleed light. If you use an LCD based phone in the dark, everything looks sharper because there is no reflective light. Also, you will see a hue on the screen. Many iPhone holders complained of yellow or bluish hues. The yellow was caused by the light shining off the back of the screen. The blue is cause by the light bouncing off the back of the screen.

HDTV;s are a bigger problem. They are basically giant monitors with a TV tuner inside. Since they are backlighted, you can see the black isnt dark, but has a soft tone..usually blue as blue warm is less disruptive to color.

The downside to LED/OLED/AMOLED screens is they suck at whites. Because the whites are not natural. How can they be because there is no light. So the white is warm, which makes them look dull. Increasing brightness helps, but that means more battery drain. Games with white backdrops that move, also use more juice. But when watching movies that are dark, AMOLED screens look best as no white from a light bulb is making the dark appear lighter.

LCD's are great for web pages because text looks sharper because the white is brighter.
To ask which screen is better will really depend on where and how you use it. If you are a person outside, use AMOLED screens...if you are inside most than use LCD's. If you play lots of games...AMOLED can be better if games are dark and eerie.

Edited by Hi_XPecTa_Chens, Jan 18 2013, 10:55pm :

This is why I'm not using the black background on my WP7 instead of the white. I always used the white but I started noticing that my 2 year old phone's battery was losing its strength. It reached the point where I had to recharge every day or it would die halfway through the second day. With the black background it lasts a little over two days.

I agree with what others are saying.
A black screen would even use more power on a LCD since a current needs to be applied to make the pixels stop the light from behind.

good thing windows phone has predominantly black backgrounds. only if more OEMs would put SAMOLED screens in their phones

If it's Super AMOLED Plus (or any AMOLED screen without the PenTile Matrix), then yes please! But since the HD Super AMOLED screens use the PenTile Matrix (which, albeit doesn't suck as much as a standard Super AMOLED screen), I much prefer the ClearBlack IPS display on my Lumia 920 to the HD Super AMOLED display on the ATIV S, just as I preferred the Super AMOLED Plus display of my Focus S to the Super AMOLED display of my Focus.

"However, the app running the black background..." Unless my eye's deceive me, the screenshot being referred to actually has a very dark blue - not black background!!

Ditto. I was about to post the same. If you are using LED/OLED/AMOLED then using black is very efficient but LCD/Super LCD, it is another story.

wrack said,
Ditto. I was about to post the same. If you are using LED/OLED/AMOLED then using black is very efficient but LCD/Super LCD, it is another story.
Well sotra. And LCD panel doesn't produce black. The imitate black. OLED or AMOLED screens are black. BIG DIFFERENCE.

LED screens are like all tiny little colors light bulbs. COlor is produced with an on/off lethod. LCD's are always on even when using blacks. Color in this case is equal to heat. The more heat the brighter the color. Black will be warm because it is dark, but it does use some power. On LED screens no power is use for black at all. Black is always cold. Cold means no heat...no heat means no power consumption.

TechieXP said,
Well sotra. And LCD panel doesn't produce black. The imitate black. OLED or AMOLED screens are black. BIG DIFFERENCE.

LED screens are like all tiny little colors light bulbs. COlor is produced with an on/off lethod. LCD's are always on even when using blacks. Color in this case is equal to heat. The more heat the brighter the color. Black will be warm because it is dark, but it does use some power. On LED screens no power is use for black at all. Black is always cold. Cold means no heat...no heat means no power consumption.

Thanks. I knew that and that is what I said but without technical details

This surely only applies to AMOLED displays. Since with LCD displays (given they don't use dynamic contrast shenanigans) the backlight always uses the same amount of energy the content displayed on the screen has no impact on battery life.

numbers will be different but generally the same principle. Black is kind of cheating though... and especially comparing it to a purple. I mean black is a primary colour, and most purples require using every spectrum to generate. I would say it's less a light vs. dark and more a primary vs. blended colour issue.

I'm pretty sure you are correct. I have a feeling they are talking about AMOLED screens here.

Microsoft has been talking about this for years now. It's a huge motivating factor behind the solid black backgrounds in Windows Phone.

NastySasquatch said,
numbers will be different but generally the same principle. Black is kind of cheating though... and especially comparing it to a purple. I mean black is a primary colour, and most purples require using every spectrum to generate. I would say it's less a light vs. dark and more a primary vs. blended colour issue.
Black is a tone not a colour. In theory, it should be no color at all.

oliver182 said,
Can't be the same for AMOLED vs LCD, right?

Correct, it is going to depend on the technology of the display.

If the display is using a 'masking' color matrix with a backlight that is 100% on no matter what pixels are used, there would not be a power difference.

However, newer display technologies are using AMOLED and even variation of per pixel lighting technologies on traditional LCD technologies. It is in these devices that using less 'light' pixels (not necessarily even black), will yield a better battery life.

If you notice with WP7/WP8, Microsoft has push the 'dark' background, but also includes the 'white' background for users that have a display technology that would not save power based on the display technology and like the lighter theme.

LauRoman said,
Black is a tone not a colour. In theory, it should be no color at all.

That's like saying zero is a percent, so if I say, "A certain percent of our product is made from recycled material", than I am theoretically correct even if it is zero percent.

LauRoman said,
Black is a tone not a colour. In theory, it should be no color at all.
False...black isnt a color...it never has been. Yes in school we are taught black is a color, but it is not. Black is nothing. It is not a tangible object. Black is naturally produce by draining away light. To produce color you must have light. Light is made up of 3 main colors...RED GREEN BLUE....or RGB. You can not produce black. Black is devoid of any color. You can't mix any colors to get black, because black isnt a color. If you turned off the sun it would be black because it would be devoid of color. Clothes that are black, use a dye...which is a chemical agent that has no color factors.

blackjezuz said,
ease of access--> HIgh Contrast

7.5 doesnt seem to have that option, but I imagin if it's anything like the High Contrast settings in the desktop versions of windows, then it looks awful.

*goes looking for screen shots*

Heh, not bad. I take it the white background isn't optional in that mode?

Edited by FiB3R, Jan 18 2013, 12:14am :

LauRoman said,
Using less pixels or less power per pixel on a screen consumes less power. Somebody give that man a Nobel Prize.

Lol just what I was about to post lol

LauRoman said,
Using less pixels or less power per pixel on a screen consumes less power. Somebody give that man a Nobel Prize.

Not all WP8 devices use OLEDs. Mine doesn't. These backgrounds would draw the same power.

LauRoman said,
Using less pixels or less power per pixel on a screen consumes less power. Somebody give that man a Nobel Prize.

And somehow you missed the point entirely in your attempt to make fun.

power per pixel?

It is about adjusting the pixel 'colors' to take advantage of how most displays use power to conserve power. Different colors, use different levels of power on some displays, and it is not about the pixel being white or black. (A black pixel is 'turned' on, just as a 'white' pixel is turn on depending on the type of display.)

Mordkanin said,

Not all WP8 devices use OLEDs. Mine doesn't. These backgrounds would draw the same power.

Actually an AMOLED would be more subject to pixel power differences than generic LCD or backlighted display technologies that mask the backlight.

So a Black background on 99% of OLED displays would consume significantly less power as they are per pixel turned on and off via the transistors on the film.

Which is why I used a black wallpaper on my Focus and Focus S. Nearly zero power draw when turning my phone on to check the time. But, now I have a Lumia 920, and it doesn't matter.

thenetavenger said,

Actually an AMOLED would be more subject to pixel power differences than generic LCD or backlighted display technologies that mask the backlight.

So a Black background on 99% of OLED displays would consume significantly less power as they are per pixel turned on and off via the transistors on the film.

That would be basically what I just said...

Anthony S said,
Which is why I used a black wallpaper on my Focus and Focus S. Nearly zero power draw when turning my phone on to check the time. But, now I have a Lumia 920, and it doesn't matter.
I use to always use dark wallpapers too...then I got a Note 2 which has a 3100Mah batt, and it lasts all day....even with live wallpapers.

aviator189 said,
what? i think i'm right..


The lesson? Creating an app with a darker background will use less energy. That is, of course, a good thing.

You were wrong

link6155 said,

You were wrong

"Which background image uses more power on Windows Phone 8?"

Has everyone forgotten the question? No, he was correct. The left one uses more power. The right one, darker, uses less.

Tidus4eva said,
You're about as right as I am a girl (hint, I'm not a girl)

Read the article title. He's right, so you're now a girl.

And this test seems to have been done on a phone with an OLED screen, because with LCD the power draw should be about the same. But if something is black with OLED it literally turns the black pixels off so no power goes to them. It's why black really is black on something like a Galaxy S3 or Samsung ATIV S, and not just really dark grey like on a LCD (you get light leakage from the back light, which OLED don't have).

Tidus4eva said,
You're about as right as I am a girl (hint, I'm not a girl)
You're right...cause girls actually read...guys dont. He was right.

The answer is obvious, because black isnt a color. Phones dont produce blacks. This is why LED screens are BETTER than LCD screens. LCD screens dont ever look blacks and blacks are never dark because of the backlight. AMOLED screens only turn on lights where color is needed thus using less energy.

If you look at most graphic intense games, the background is always bright in color in most cases. It requires more juice to run it as well, making the CPU get hotter. Games with naturally dark or even artificially dark backdrops run color because the screen wont waste any energy making black.

I learned this in 5th grade in art class....
Black is a COLD color while white is a HOT color. Think about it. COLDER @ night. Hotter during daylight.