Energy use and high contrast/dark modes/flux/redshift

[Lionel Trébuchon]

Hello everyone!

I haven't been able to find relevant information about this question on google.
I am wondering if a darker screen on the surface pro 3 uses less energy than a brighter one.
Are all the leds on the screen automatically on, or is a dark spot on a screen also synonym with off-switched LED.
I found this on laptomag.com:
"The LED backlights in most notebook “LED” displays use the same amount of power no matter what is shown on screen. Displaying greater areas of black on the display only “blocks” the light emitted from the backlight, the backlight intensity isn’t reduced in most cases. If anything, for a TN LCD panel to display black, you need to apply voltage to the crystals so displaying black on a LCD actually uses more power than displaying white. You can google this.
Only emissive display technology such as Plasma, CRT or AMOLED use less power the more areas of black is displayed on the screen."

So apparently the question would resolve to "Is the surface screen Plasma, CRT or Amoled like?"

Thanks a lot for any answers!
I am in general interested in reducing my eye strain while reading PDFs and I wonder if a high contrast mode would help my eyes and even also reduce the consumption => that'd be great!

Thanks, and have a wonderful day!
Lionel

 

[GreyFox7]

IDK I think Redshift only comes in to play for astronomical bodies moving out in space or if your traveling really fast.

What year was that laptop mag article it sounds old.
The Surface screen is not Plasma or CRT one spec I saw stated it was IPS/PLS
Screen brightness set to 40% definitely uses less energy then when set to higher values.

As for high contrast I have never tried it. Use the combination of settings most comfortable to you as everyones eyes are different.

 

[nipponham]

SP3 is an LCD with IPS technology, so it is non-emissive and blacks will use the same amount of energy to produce as whites.

If eye strain is your concern, yes high contrast colors will help. You can also try a blue light screen filter.

 

[lhauser]

I find using high contrast mode all the time to be inconvenient. In Chrome, I use the Hackervision extension, which makes it easy to turn high contrast/reverse colors on with the click of a button. Since I seem to spend more than half my time in a web browser, it's an easy-to-use remedy for all that white background.

 

[kristalsoldier]

IDK I think Redshift only comes in to play for astronomical bodies moving out in space or if your traveling really fast.

What year was that laptop mag article it sounds old.
The Surface screen is not Plasma or CRT one spec I saw stated it was IPS/PLS
Screen brightness set to 40% definitely uses less energy then when set to higher values.

As for high contrast I have never tried it. Use the combination of settings most comfortable to you as everyones eyes are different.

This is interesting. Any particular reason why the energy efficiency is at exactly 40%? Is it the case that at 35% there is more energy inefficiency than at 40%? Thanks.

 

[GreyFox7]

This is interesting. Any particular reason why the energy efficiency is at exactly 40%? Is it the case that at 35% there is more energy inefficiency than at 40%? Thanks.

Sorry if I misled with that... the dimmer you go the less energy used.
At Zero we might not see it ... we could call that Stealth Mode

 

[kristalsoldier]

Sorry if I misled with that... the dimmer you go the less energy used.
At Zero we might not see it ... we could call that Stealth Mode

Thanks! Perhaps I was reading a bit too literally.

 

[Lionel Trébuchon]

Hello nice people!

Thanks a lot for your fast responses, I didn't see them because the notification ended in the spam of my gmail!
Yes, I also use hacker vision, it's great!
High contrast doesn't seem to be integrated fine in most of programmes so it's true that I nearly don't use it at all.
Thanks nipponham and greyfox7, that were exactly the answers I was searching for.

Nipponham, you are stating that no colour at all is emissive? But when you turn the light of your room off, in the dark, you can see the surface emits light. Is "non-emissive" defined by the fact that's it emits under a certain intensity of energy?

Thanks a lot for your kind responses.
Lionel

 

[nipponham]

Nipponham, you are stating that no colour at all is emissive? But when you turn the light of your room off, in the dark, you can see the surface emits light.

Your question as stated doesn't make sense, but I think you're asking if power is needed to output black colour... Is that correct? In the case of SP3's LCD screen, the answer is yes. It doesn't matter what colour is displayed on screen. It will generally need the same amount of external light source to display colour at a given brightness level, whether they are "dark" or "light".

Is "non-emissive" defined by the fact that's it emits under a certain intensity of energy?

Non-emissive is defined by the fact that LC molecules cannot emit light on their own, unlike OLEDs or plasma display. In those technologies, each pixels use energy to display colour, and since black, (no light), uses less energy to produce than white, what is output on the screen will have an effect on energy/battery consumption.

 

[Lionel Trébuchon]

Hello dear nipponham!

You're truly great, thanks! But this time I have to admit you have more confused me than enlightened me.
Yes, you are right, my ultimate goal is just to know if having a screen more black than white, results in less energy use of a SP3's LCD screen. Unlike in my badly stated introductery question. I am not talking about brightness at all. For clarification purposes, I have made a screenshot of this page as I am reading it, with the Chrome extension "Hacker Vision" on.

1) You are talking about external light in the first part of the response. I don't really know what you mean by that, but I guess it comes from my very poorly stated question with the dark room. "Black and white need the same amount of light to be displayed at a certain brightness level." I think I understand that. If you shine light on an object, the more light you shine on it, the brighter it will reflect its colors. Black would also appear "brighter" as the colors around are brighter and stand in contrast to black. Is that right?

2) Your second answer seems to be more what I was searching for. You state that black uses less energy to produce than white (I would have thought it uses 0 energy), thus having a mainly black screen would reduce battery consumption. The article I cited was this one, from 2012: http://blog.laptopmag.com/top-windows-7-battery-savers .

3) As you seem to know yourself around this topic, can you maybe fastly (please don't lose your time with this) tell me how having so much black instead of white affects battery life on

• AMOLED
• LCD with TN
• LCD with IPS
• CRT
• Plasma

Thanks a lot dear Nipponham, and others!

Greetings,
Lionel

 

[ptrkhh]

AMOLED: Yes, black saves battery
Everything else: No
And SP3's screen is unsurprisingly in the second camp

 

[nipponham]

@Lionel

1) By “external light source” I mean that non-emissive displays need some source of light. Emissive displays (plasma, CRTs OLEDs, etc) emit light on their own (under electrical charge) and do not need an external light source. Your idea that “black appears brighter because the other colours around it are brighter” is a little bit off the mark. Black may appear “lighter” because of the amount of light output (brightness). If you turn down the amount of light (i.e. brightness), black may look darker, but light colours such as white will look darker as well.

2) Black uses less energy for emissive displays only. As for black using zero power, if it’s true black (#00000), technically speaking, for OLEDs, yes. For other emissive displays, no.

3) I don’t know of any battery-powered CRT or plasma device. Some people still say CRTs look better than LCDs, but they are an energy hog. Plasma also uses more energy than AMOLEDs and LCDs and are only viable as large screens (>40 inches). AMOLEDs are the best so far in terms of energy use and contrast, then LCDs.