Icon of program: LightBulb

LightBulb for Windows

  • Free
  • 5
    6
  • 4.7K
  • V2.6.3
Free Download for Windows

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Gamma adjustment utility for PC

LightBulb is a free utility tool that was created by indie dev Alexey Golub for PC. This open-source software can be used to dynamically adjust gamma levels being displayed by monitors. It does so based on the time of day as it transitions from morning to afternoon, and night.

Top Recommended Alternative

LightBulb utilizes a similar concept F.lux or CareUEyes in that it attempts to reduce eye strain by changing the color temperature of computer monitors from the cool blueish shade to a warmer and more relaxing orange color. It's easy to set up and boasts a simple and intuitive user interface.

How does it compare to F.lux?

LightBulb is essentially a free and open-source alternative to the ever-popular blue light filter tool, F.lux. If you've used the latter before, the former will provide a familiar user experience. 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. Once installed, you enable and configure it from your system tray.

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

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. Use global hotkeys to change settings on the fly and even whitelist certain applications that require color accuracy. One thing that needs more work, though, is more granular control over the color temperature adjustment slider—something that F.lux still does better.

A great alternative

All in all, if you're looking for a free and open-source alternative to F.lux, LightBulb might just fit the bill. It's fast and lightweight, offers virtually the same set of features and options, and is equally intuitive to use, as well. It doesn't offer as much control over color temp adjustments, but if you're okay with that, this is worth considering.

  • Pros

    • Fast and lightweight
    • Free and open-source
    • Intuitive to use
    • Plenty of customization options
  • Cons

    • Imprecise control over color temperature
 0/2

App specs

  • License

    Free

  • Version

    2.6.3
  • Latest update

  • Platform

    Windows

  • OS

    Windows 11

  • Downloads

    4.7K

    Last month's downloads

    • 83
  • Size

    16.24 MB

  • Developer

Program available in other languages


Icon of program: LightBulb

LightBulb for PC

  • Free
  • 5
    6
  • 4.7K
  • V2.6.3
Free Download for PC

View an ad to download for free


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Laws concerning the use of this software vary from country to country. We do not encourage or condone the use of this program if it is in violation of these laws.
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Is LightBulb safe?

98/100

Score result: Clean

This file passed a comprehensive security scan using VirusTotal technology. It is safe to download.

  • Virus free
  • Spyware free
  • Malware free
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Scan Info

Last scan
Monday, May 4, 2026
Scan provider
VirusTotal · Full report

File Integrity

File
2.6.3.exe
SHA256
cfae2d6e77b4660f22a1f7d5478db5b09963a6476be322f46a2e1ca7a2f2a586
SHA1
b577bf744aa6ea96bedb04bdf38c35c36cb4cd00

Softonic security commitment

LightBulb has been thoroughly scanned by our advanced security systems and verified by industry-leading partners. This file comes from the official developer and has passed all our security checks, showing no signs of viruses, malware, or spyware. For more information, visit our Security and Trust Center