Hi, bjhansen.
Thank you for visiting Apple Support Communities.
I understand that your MacBook Air display is darker than usual. Lets start with adjusting your brightness by going through System Preferences. You may want to disable Automatically adjust brightness temporarily to see if this corrects the issue.
- If you have a Mac with ambient light sensing, choose Apple menu > System Preferences, click Displays, then click Display. Select “Automatically adjust brightness.”
- Choose Apple menu > System Preferences, click Displays, then click Display. Drag the Brightness slider to adjust the brightness of your display.
OS X Mavericks: Adjust your display’s brightness
If this issue persists, try resetting the System Management Controller (SMC).
Resetting the System Management Controller (SMC) on your Mac
Cheers