SunsetScreen v1.25

(free for personal use, not for commerical purposes, or within a commercial setting without permission)

(900k size, last updated 2016-08-28)
Requires .NET 3.5 or higher (your PC probably already has it).

Portable version: here (600k)

Intro | Background | History | Documentation | Contact

SunsetScreen is a free Windows app (for personal use) which helps take the glare off your your screen in the evening. Scientific research has shown that melatonin - the chemical the brain makes late in the day - is reduced when exposed to blue light. By tempering this blue light, it becomes easier to wind down properly at night, and thus have a more restful sleep.

Whether you're a morning lark or night owl, SunsetScreen allows you to set the time of the sunset and sunrise, so you can have full control over your sleep cycle.

Download SunsetScreen

Background and motivation behind SunsetScreen:

In the evening and at night, computer screens are starkly blue compared to the 'natural' orange glow provided by indoor lighting. With SunsetScreen, it's easy to dim our screens to an orange-ey hue to match the colour of the indoor lighting we use. Additionally, scientific research has found that along with over-bright indoor lighting, over-bright screens can affect the production of melatonin - the chemical which helps us to turn off at night to get a restful sleep.

Programs such as F.lux partially solve the problem, but in the winter, I found the sunsets came too early. This caused F.lux to darken the screen early too. Just because it's dark outside early, that does not mean the human body clock revolves around the winter's schedule. Many, perhaps most people find considerable benefit to extra light during the day during the darker seasons, and if this extends to your laptop, tablet or computer screen, then we should allow that!

Morning larks, night owls and even those who work night shifts will benefit from using SunsetScreen because their sleep cycles are hours apart from each other. SunsetScreen can be tailored so you can set the sunset and sunrise times appropriately to match your sleep rhythm.

We should also be able to define the colour of the filter by hue, saturation or brightness if need be. This way, we can match the colour more precisely to the illumination by the light bulbs we have in our houses. Although dimming the amount of blue light is most important, the overall brightness may also be dimmed too if you so wish.

Features include:

  • Set the sunset time precisely.
  • Set the sunrise time too.
  • Choose by colour temperature or by HSB for a precise colour.
  • Transition from one phase to the other gradually.
  • Automatically resides in the tray so it keeps out of your way.
  • Loads automatically at Windows startup if you wish.
  • Instantly turn off SunsetScreen if you need to do colour sensitive work.
  • Choose from a range of presets, and reset to default if things go wonky.
  • Small, fast, elegant and easy to use interface in less than a megabyte.
  • Isn't patent pending unlike something beginning with 'F' ;)

  • Documentation is available here.
    I can be emailed here.
    Here is the PAD file.


  • 2016-08-28: v1.25 - Fixed fading issue on last day of each month.
  • 2016-06-10: v1.24 - Added invert day/night mode and fixed display of "Expand colour range" if already expanded.

  • 2015-08-21: v1.23 - Windows 10 compatible, and new 'Hide on manual start' option.

  • 2015-07-09: v1.22 - New 'Invert colours' mode - perfect if you need the darkest screen possible.

  • 2015-06-16: v1.21 - Fixes memory error message on some systems if you tried to log off Windows and on again.

  • 2015-05-06: v1.20 - On some systems, the colour of the screen would return to normal white after a UAC prompt, or PC unlock occurred. This should now be fixed. SunsetScreen should also now have full support for multiple monitors. Extra features include new and improved custom hotkeys functionality, Options window, and numerous tweaks.

  • 2015-03-29: v1.18 - Fixed 'bug' which may cause a slight, but noticeable flicker for some users. This was originally added to act upon any unforseen changes back to the default screen's colour from the OS, but affected systems are relatively rare. See the docs though if you find the screen occasionally goes back to default (when it shouldn't) as you can set the 'periodicallyUpdateScreen' parameter to true to bypass this problem.

  • 2015-03-29: v1.17 - Fixed bug which may prevent the return to normal screen colours after exiting SunsetScreen. Also added tray menu item to turn SunsetScreen on/off. Finally, because of the maturity of SunsetScreen, by default, "Load on Win startup" is now ticked.

  • 2015-03-28: v1.16 - Keyboard shortcut to turn on/off SunsetScreen. Also included masterBrightnessIncrement setting for power users.

  • 2015-03-28: v1.15 - Minor GUI tweaks and disabling of keyboard shortcuts until colour range has been expanded to reduce potential confusion.

  • 2015-03-27: v1.14 - Added keyboard shortcuts Alt+PageDown and Alt+PageUp to control the brightness independently of the main app's controls. Also, 4100K Moonlight is the default colour temp on first use now. Reinstalling the app will now automatically close the older version.

  • 2015-03-25: v1.13 - Closing the app with the standard close button keeps SunsetScreen active. You can still close the app with the Exit button if you wish.

  • 2015-03-21: v1.12 - Thanks to everyone who has helped support SunsetScreen with suggestions and error reports. Bug fixes in this release are: Easily resetting Windows XP is now possible without closing the program first. The button to reset that current colour to default is now called "Default" instead of "Reset" to differentiate it from the main "Reset..." button.

  • 2015-03-20: v1.11 - Minor tweaks and fixes. The 12-hour clock format is now default again.

  • 2015-03-20: v1.10 - Big bug fix to solve crashing when changing to sunset/sunrise in many countries. Editing a single line of code did the trick. I can also now reproduce the errors on my setup, so if any future errors do crop up (which I doubt), I'll be onto them in minutes.
    Also fixed crash when trying to change the Delay until sunset (which only appeared in 1.05).

  • 2015-03-19: v1.05 - Has 24 hour mode option (default) and is more compatible for worldwide usage.

  • 2015-03-18: v1.04 - New 'Info' checkbox which displays more detailed information should you choose. Also overhauled system for expanding the colour range (until you do, certain options are now greyed out or restricted for sanity's sake). Finally, colours are more numerically precise.

  • 2015-03-17: v1.03 - SunsetScreen now allows you to select ALL colours including darker shades. Simply look for the bright orange button that will appear when you try, click it, then click Yes to the prompt, and then reboot, and voila.
    Resetting to factory settings also now doesn't affect the "Load on Win Startup" setting.

  • 2015-03-17: v1.02 - Switched default mode to "Cool Incandescent" whilst I figure out a way to allow Windows 8+ to support darker screen modes.

  • 2015-03-16: v1.01 - Preferences are autosaved after controls are changed (before, you needed to manually close SunsetScreen for it to save).
    Also fixed bug when occasionally certain Windows prompts may turn the screen back to normal and SunsetScreen didn't respond afterwards.

  • 2015-03-15: v1.00 - First release!

  • SunsetScreen is copyright Daniel White 2015 onwards. I can be emailed here