Working late into the evening in front of a bright computer monitor exposes eyes to high concentrations of artificial blue light. Scientific studies have shown that intense blue light wavelengths suppress the brain’s production of melatonin (the hormone responsible for regulating healthy sleep cycles), leading to digital eye strain, headaches, and insomnia after nighttime computer sessions.
To promote ocular comfort and healthier sleep hygiene, Ubuntu desktop includes a built-in display feature in its GNOME desktop environment: Night Light. Night Light dynamically shifts your screen’s colour palette from cool harsh blue toward warm, soothing amber tones after sunset. This guide explains how to enable, schedule, and fine-tune colour warmth for Night Light in Ubuntu.
How Night Light Protects Your Eyes
Rather than simply dimming display brightness (which can cause squinting):
- Colour Temperature Adjustment: Standard daylight displays operate at approximately 6500K (cool white/blue). Night Light warms the panel down to 4000K or 3000K (warm amber), filtering out aggressive short-wavelength blue light.
- Astronomical Synchronization: Ubuntu can query your local geographic sunset and sunrise times, gradually warming the screen as twilight falls and returning to crisp daylight colours in the morning.
- Zero Performance Overhead: Built directly into the Wayland and X11 display compositors, requiring no third-party background software like f.lux.
Step-by-Step: Enabling Night Light in Ubuntu Settings
- Open the System Menu by clicking the network/volume cluster in the top-right corner of the Ubuntu top bar.
- Click the Settings icon (the gear cog).
- In the Settings window, click Displays in the left navigation sidebar.
- Click the Night Light tab at the top of the display settings pane.
- Toggle the Night Light switch to ON.
Your screen will immediately preview the warm amber color shift.
Customising the Night Light Schedule
Ubuntu allows you to control exactly when the colour shift activates:
- Sunset to Sunrise (Recommended): Select Sunset to Sunrise. Ubuntu uses your approximate location to calculate precise astronomical twilight times, shifting colours automatically as the seasons change throughout the year.
- Manual Schedule: Select Manual Schedule if you work night shifts or prefer fixed times. Specify custom From (e.g. 20:00) and To (e.g. 07:00) times using the time selector dials.
Fine-Tuning Color Temperature Warmth
Every user’s eyes and monitor panels have different colour sensitivities. To adjust how warm the display turns:
- In the Night Light settings panel, locate the Color Temperature slider.
- Drag the slider to the left for a gentle, subtle warmth (closer to natural paper).
- Drag the slider to the right for a deeper, rich amber tone (maximum blue light reduction for dark rooms).
Quick Toggle via the Quick Settings Menu
If you occasionally edit photos or watch a movie where colour accuracy is paramount, you do not need to open Settings to disable Night Light:
- Click the top-right Quick Settings menu on your Ubuntu desktop.
- Click the Night Light tile (represented by a crescent moon icon) to toggle the feature on or off instantly with one click.
Display Comfort Comparison
| Setting | Standard Daytime Display | Night Light Active |
|---|---|---|
| Colour Temperature | Cool White (6500K) | Warm Amber (3000K – 4500K) |
| Melatonin Impact | Suppresses natural sleep signals | Minimises sleep rhythm disruption |
| Eye Fatigue in Dark Rooms | High glare and optical strain | Soft, comfortable reading contrast |