Most laptops have on the keyboard the appropriate keys that allow you to adjust only the brightness. However, the contrast can be easily changed in the driver settings of the video card built into the laptop.
If the laptop has a video card from Nvidia, the display contrast can be adjusted using the control panel driver. To do this, click the right button of the touchpad (or mouse) on the desktop and select "Nvidia control Panel".
Click "adjust color settings in the desktop by using the links at the left side of the program window. Select "Use Nvidia settings" then adjust the desired level using the slider under "Contrast".
If the laptop has a graphics card from ATI, then download the latest version of the Catalyst drivers. It is similar to the control panel options from Nvidia. Go to tab color on the left side of the program screen. Adjust the contrast with the corresponding Contrast slider, and then apply the settings made.
For integrated graphics Intel Graphics is enough to choose in the driver settings, the item "Graphic features" -> "color Settings", where with the help of the slider you can set the desired parameters of brightness and contrast.
To change the contrast directly when watching movies or any images, you can use the functions of your application. For example, in VLC media player access to such settings is found in the Extended Settings menu "Tools" program. In the third-party image viewer software also provides function settings display, which is located in "Options" - "display settings" ("setting image").