The arrow button is a 24-hour preview that shows how it will appear over 24 hours in around 15 seconds. LightBulb sits in your system tray, and once opened, you can quickly set up and test various colors, temperatures, and duration. It doesn't offer as much control over color temp adjustments, but if you're okay with that, this is worth considering.LightBulb continuously changes the screen gamma using temperature profiles, making the colors appear warmer at night or any way you like. It's fast and lightweight, offers virtually the same set of features and options, and is equally intuitive to use, as well. A great alternativeĪll in all, if you're looking for a free and open-source alternative to F.lux, LightBulb might just fit the bill. One thing that needs more work, though, is more granular control over the color temperature adjustment slider-something that F.lux still does better. Use global hotkeys to change settings on the fly and even whitelist certain applications that require color accuracy. While the program will automatically detect your location and adjust gamma levels accordingly, you can still opt to manually set a location of your choice. You can even view a preview to see how this will transpire over a 24-hour period so you can tweak it to your preference.

The third slider is for setting the duration at which one will transition to the other.

Once installed, you enable and configure it from your system tray.Īccess LightBulb's configuration options, and it will provide you with three main sliders to you can use to adjust color temperatures for both daytime and nighttime.

It works in a similar way in that it is able to adjust the gamma levels of your screen dynamically based on your geolocation and time of day. If you've used the latter before, the former will provide a familiar user experience. LightBulb is essentially a free and open-source alternative to the ever-popular blue light filter tool, F.lux.

Free for mac download LightBulb 2.4.6