Lumen

Lumen is a macOS menu bar application that automatically adjusts screen brightness based on what is displayed on the screen. Instead of only reacting to ambient light, it looks at screen content and changes brightness to make bright and dark windows more comfortable. It can brighten the display when the user is working in a dark terminal and dim it when a bright web page is open. Users train the app naturally by adjusting brightness with the normal keyboard brightness keys. The app requires screen recording permission because it samples the display to understand whether the content is light or dark. Overall, it is a practical comfort utility for people who switch between dark and bright apps, especially at night.