Tyrrrz/LightBulb: Windows Gamma Adjustment on a Sunrise and Sunset Schedule

What LightBulb Actually Changes, and for Whom

LightBulb is a Windows application that reduces eyestrain from staring at a screen during late hours. The README states the mechanism plainly: as the day goes on, it continuously adjusts gamma, transitioning the display colour temperature from cold blue in the afternoon to warm yellow during the night. The stated objective is to match the screen to the light sources around you, sunlight during the day and artificial light at night.

The intended user is someone on Windows who works into the evening and wants the screen to follow the sun rather than a fixed schedule. The feature list includes location-based sunrise and sunset times, manual sunrise and sunset times as a fallback, a whitelist for colour-sensitive applications, global hotkeys for adjusting on the fly, and smooth gamma transitions. The README also states that it works without an internet connection, which matters if the location lookup is unavailable or you would rather not have the app reach the network.

This is not a calibration tool. It does not measure your panel, produce ICC profiles, or correct colour for print and design work. It changes gamma on a time curve. If your problem is that a specific monitor renders skin tones wrong, LightBulb is aimed at a different problem.

How the Gamma Curve and the Whitelist Interact

The repository layout shows the split the README does not spell out. There is LightBulb.Core, a library, and LightBulb.Core.Tests alongside it, then LightBulb.PlatformInterop for the Windows-specific calls, and LightBulb for the application itself. That separation suggests the scheduling and colour maths live in Core, while the platform layer handles applying gamma to the display. The README does not document the exact interpolation between the afternoon and night endpoints, so treat the curve shape as unverified.

Two inputs drive the schedule. Either the app derives sunrise and sunset from your location, or you set them manually. The README lists both as features and does not state which takes precedence when both are configured, which is a real gap if you travel and want a fixed schedule.

The whitelist is the more interesting mechanism. It exists for colour-sensitive applications, meaning apps where a shifted white point would distort your judgement of colour. The README does not explain how the whitelist is keyed (by process name, window title or executable path) or whether gamma is restored to neutral when a whitelisted window has focus. That is the first thing to check in the wiki if you plan to rely on it while editing images or video.

Installing LightBulb on Windows

The README points to the releases page for the stable build, and to the GitHub Actions workflow for a CI build. It also lists three package managers, all marked community-maintained, with the note that community-maintained packages are published independently from this repository and may not always be up to date with the latest release.

The WinGet command from the README is:

winget install Tyrrrz.LightBulb

After it runs, LightBulb should be installed and available from the Start menu. The README does not describe first-run behaviour, so the dashboard and settings screenshots in the repository are the only preview of what you configure.

The Scoop and Chocolatey alternatives are listed as:

scoop install extras/lightbulb
choco install lightbulb

Both are community-maintained, so the version you get may lag the stable release. If you need the current build, the README directs you to the releases page instead. For the first real use, open the settings and choose between location-based and manual sunrise and sunset times, then add any colour-sensitive applications to the whitelist. The README does not give the exact UI labels, so expect to find these under the settings screen shown in the repository screenshots.

Where LightBulb Is the Wrong Tool

LightBulb is Windows-only in practice. The repository contains a LightBulb.PlatformInterop project and the download section lists WinGet, Scoop and Chocolatey, all Windows package managers. Nothing in the README describes a macOS or Linux build. If you need the same behaviour on a Mac or a Linux desktop, this project is not the answer regardless of how well the gamma curve suits you.

Gamma adjustment is also not colour management. It changes the output curve globally, which is exactly why the whitelist exists. If you do colour-critical work, a global gamma shift is a liability unless the whitelist reliably neutralises it, and the README does not document that behaviour.

There is a second limitation in the documentation itself. The README states that questions and issues should go to the wiki, and the wiki is where the operational detail lives. The README does not document rollback, does not describe what happens on multi-monitor setups with different panels, and does not state how the app behaves if it exits unexpectedly while gamma is shifted. Those are the questions to resolve before deploying it on a machine you cannot easily reconfigure.

LightBulb Compared with f.lux

The obvious comparison is f.lux, which solves the same problem of shifting display colour with the time of day. The difference in approach is in the project structure and the packaging story rather than in the core idea. LightBulb is a C# application with its logic split into LightBulb.Core and its Windows integration in LightBulb.PlatformInterop, distributed through GitHub releases and three community-maintained Windows package managers. f.lux is a separate product with its own distribution and its own set of platform targets.

If your environment is Windows and you install software through WinGet, Scoop or Chocolatey, LightBulb fits that workflow directly. If you need a tool that covers macOS as well, the README gives you no path here. The honest summary is that both tools do gamma shifting on a schedule; LightBulb's distinguishing features in the README are location-based sunrise and sunset, a whitelist for colour-sensitive applications, and global hotkeys. Compare those three against whatever you use now rather than comparing the general concept.

Maintenance, Licensing and Upgrade Cost

The repository is not archived, and the last push was on 2026-09-10. The most recent release, 2.7.2, is dated 2026-09-10 as well, with 2.7.1 on 2026-05-19 and 2.7 on 2026-03-10 before it. The README carries a status badge labelled maintenance, which is consistent with a release cadence measured in months rather than weeks. Plan upgrades around those releases rather than expecting continuous churn.

The project is MIT licensed. That is permissive: you can use, modify and redistribute it, including in commercial settings, provided the licence terms are honoured. This is not legal advice; read License.txt in the repository if the terms matter to your organisation.

Upgrade cost is low in the sense that the app is a desktop utility with no server component and no database. The README does not describe a configuration migration path between versions, and it does not document whether settings carry over automatically. If you have tuned sunrise and sunset times or built a whitelist, check that those survive an upgrade rather than assuming they do. The community-maintained packages add a second variable: the README warns they may lag the latest release, so a package upgrade and a release upgrade are not the same event.

Editorial conclusion

Adopt LightBulb if you work late on Windows and want gamma transitions tied to your location's sunrise and sunset rather than a fixed clock, and if a small C# project with a wiki as its main documentation channel is acceptable to you. Do not adopt it for macOS or Linux, for per-monitor colour calibration, or where you need a published API or a documented rollback path. Verify first that the WinGet, Scoop or Chocolatey package you intend to use is current, since the README states those packages are community-maintained and published independently from the repository, and confirm the whitelist entries you need for colour-sensitive applications before relying on the transition.

Frequently asked questions

Official sources

1. License: MIT
2. Project website
3. README
4. Releases
5. Tyrrrz/LightBulb on GitHub