To change the brightness of the backlight of the laptop is Acer use the combination of Fn and arrow buttons left and right. Usually the up and down arrows when pressed simultaneously with Fn adjust the volume of the audio device, but some older models may meet this combination to control brightness. With this parameter, you can also view the Internet by typing into a search engine your model name or check the user manual that comes with every laptop.
If you need to adjust not only the brightness but also the parameters of the image itself, open the properties of the desktop by clicking on it with the right mouse button. A little window opens appearance settings of the operating system, go to the Settings tab.
Click "Advanced". You will have a new window where you can adjust various settings relating to input devices and graphical output. Navigate to your graphics card, usually called respectively the model of your adapter.
Find the button "Graphics" or anything that has a similar function. Also, for opening this window in some models, responds to Alt+Ctrl+F12.
Go to the settings menu item color. Change the setting of the image brightness by moving the pointer left or right. Here you can adjust the contrast and other items. Apply and save the changes.
If you need to find on your computer the light switch when you change power mode, open the personalization setting of the power supply. Accordingly, each mode of supply a certain brightness. If you don't want it changed, set the same value. Save the changes.
The backlight brightness and the image brightness is not the same thing.
Do not turn on the backlight of the laptop to maximum power.