What is Colour Temperature?
Colour temperature is measured in Kelvin (K) and describes the warmth or coolness of white light — whether from a monitor, bulb, or the sun. Lower values (2700–4000K) appear warm and orange; higher values (6500–10000K) appear cool and blue. The monitor industry uses colour temperature interchangeably with white balance to describe the displayed white point.
Understanding and setting the correct colour temperature is important for reducing eye strain in the evening, maintaining colour accuracy for professional work, and matching screen output to the ambient lighting in your room.
How to Use the Colour Temperature Test
Step 1 — Launch and go fullscreen. Press Launch Test, then F for fullscreen.
Step 2 — Display a white or light grey pattern. This is the most revealing background for evaluating colour temperature — the warmth or coolness of the display becomes immediately apparent.
Step 3 — Compare between OSD presets. Cycle through your monitor's colour temperature presets (Warm, Standard, Cool) while observing the white field. Note the visual difference between each preset.
Step 4 — Evaluate grey neutrality. At your chosen temperature setting, grey patches should appear free of any colour cast. A blue, yellow, or green tint in neutral grey indicates the preset is not well-calibrated on your unit.
Common Colour Temperature Presets
| Preset Label | Approximate Temperature | Appearance |
|---|---|---|
| Warm | 5000–6500K | Neutral to slightly warm white |
| Standard / Native | 6500–7500K | Neutral white to slightly cool |
| Cool / Bluish | 7500–9300K | Distinctly cool, blue-white |
| User / Custom | Adjustable | Set via RGB sliders |
Note: Preset labels vary by manufacturer and do not correspond to consistent temperatures across brands.
Colour Temperature and Eye Strain
Blue-enriched light (higher colour temperatures) suppresses melatonin more strongly than warm light. Reducing colour temperature in the evening — switching to Warm preset or enabling Night Mode — can improve sleep quality and reduce eye fatigue in low-light conditions.
Most operating systems include a blue light reduction feature: Night Light (Windows), Night Shift (macOS, iOS), and similar settings on other platforms. These shift the display toward warmer temperatures on a schedule. Using a warm OSD preset achieves a similar effect at the hardware level.
Colour Temperature and Accuracy
D65 (6500K) is the standard white point for sRGB, Rec.709, and most consumer content. Working in Night Mode or a warm colour temperature preset while doing colour-critical tasks will shift the perceived colours and reduce accuracy. Switch to a calibrated 6500K setting when doing photo editing, video grading, or any colour-dependent work.
Frequently Asked Questions
What colour temperature is best for eyes? 6500K is the standard for accurate display use. For evening use in dim conditions, 4000–5000K reduces blue light output and is less disruptive. Avoid very high temperatures (8000K+) for extended sessions as the strong blue component contributes to eye fatigue.
How is colour temperature different from white balance? They are the same concept described differently. Colour temperature is the physics measurement in Kelvin. White balance is the display/camera industry term for adjusting the white point. Both refer to whether white looks warm or cool on screen.
Does colour temperature affect colour accuracy? Yes. Accurate colour evaluation requires the correct reference white — D65 at 6500K for sRGB content. At warmer temperatures, blues appear more neutral; at cooler temperatures, yellows appear more neutral. Always evaluate colour accuracy at the correct colour temperature for your content's colour space.
Should I use Night Mode for all evening use? Night Mode or warm presets are recommended for general evening use if you are sensitive to sleep disruption. Disable Night Mode for colour-critical work — the warm shift will affect your perception of colour balance in images and video.