x220, Screen Dims based on picture content, can't turn off [ Edited ]

[barelytone]

I'm running an X220 with Windows 7 Home Premium, Core i5, intel graphics,

The issue I'm having is that when my screen is showing mostly white (like a Word file), the screen is nice and bright.  Then when I switch to something that is mostly dark, the brightness seems to turn down.

I am referring to the apparent luminosity of the backlight.  When I switch to the dark picture, the brightness of the screen will be high, and then over the course of 5-10 seconds will gradually dim.  My guess is that it (i.e. the computer/os not sure what) is adjusting the picture to something it thinks will be more readable since the overall contrast / luminosity of the display output has changed.

When I switch back over the mostly white program/window, the screen will appear dim, and over the course of 5-10 seconds, will get noticeably brighter, adjusting back to the mostly white window.  I have verified this with another person, so I am not crazy.  This thing has Intel HD3000 graphics on the Core i5 chip, but the "Graphics Options" auto adjust settings have all been disabled (things like detect movie mode, etc.).  I can't seem to find any other settings to change, but since I switch back and forth between screens an awful lot, this thing is driving me crazy.  Does anyone know what it is, and can tell me how to turn it off?

[Mr_Toad]

I've noticed the same thing. At first I thought there was something wrong with the screen, but I ended up concluding that it's just a rather peculiar way to make the battery last a little longer. It doesn't do it on external power.

I couldn't find any way to turn it off, either, but I'm more or less used to it now.

[barelytone]

Initial test confirms you're right regarding external power. If I notice a change, I'll repost. If anyone knows how to turn this off, I would still be grateful. Thanks for the post

[replax · Accepted solution]

I had that "problem" too and it is actually a setting you can disable.

Go into your Intel graphic settings, then go to power.

Make sure that the smart powersaving features are disabled. Now switch at the top from "plugged" to "unplugged" and repeat. that solved the issue for me.

I hope for you, too

[sebgus]

As replax said:

It is Intels Automatic brightness/powersaving that dims the screen.

[barelytone]

Great, thank you kindly, this did indeed fix the problem