Change Display preferences on Mac
On your Mac, use the Display pane of Displays System Preferences to adjust resolution and brightness, and to set display options.
Note: Not all options described here appear for all display models, and some options appear only when your Mac is connected to a display.
To open this pane, choose Apple menu 
> System Preferences, click Displays, then click Display.
Resolution | The amount of detail your display shows. Select “Default for display” to automatically use the best resolution for the display, or select Scaled to manually select a resolution. For instructions, see Change your Mac display’s resolution. | ||||||||||
Brightness | Controls how light or dark your screen appears. Move the slider to the right to make the screen brighter and to the left to make it darker. For instructions, see Change your Mac display’s brightness. | ||||||||||
Automatically adjust brightness or Ambient light compensation (depending on your display) | If your Mac has ambient light sensing, you can have the display brightness adjust automatically based on current light conditions. | ||||||||||
True Tone | Automatically adjusts the colors on the display based on current ambient lighting conditions. | ||||||||||
Rotation | Rotates the image shown on your display by the chosen amount. For instructions, see Rotate the image on your Mac display. | ||||||||||
Refresh Rate | How frequently your screen is redrawn. If the rate is too low, your screen may appear to flicker. If the rate is too high, the screen may be black because it doesn’t support that rate. Check the documentation that came with your display for the best rate. | ||||||||||
Show displays in menu bar | Displays an icon in the menu bar that lets you switch between your most frequently used resolutions. | ||||||||||
Overscan | If you’re using a TV as a display and you can’t see the menu bar, select this option. | ||||||||||
AirPlay Display | Use AirPlay Mirroring to wirelessly send what’s on your Mac to another display. | ||||||||||
Show mirroring options in the menu bar when available | Show devices available for AirPlay Mirroring in the menu bar. | ||||||||||
Gather Windows | Moves all open Displays preferences windows to the display where this button is. This button appears only if more than one display is connected to your Mac. | ||||||||||
Detect Displays | Scans for all the displays connected to your Mac. Press and hold the Option key to make this button appear in the place of the Gather Windows button, then click Detect Displays if your Mac doesn’t recognize a display you’ve just connected. | ||||||||||