What colour match measures
A target colour appears on the left. On the right is a second square controlled by three sliders for hue, saturation and lightness. Move them until the two squares look identical, then lock it in. Five colours make one run.
The score is Delta E, the standard measure of how different two colours look. It is computed in the CIELAB colour space, which is built so that equal distances correspond to roughly equal perceived differences. A Delta E of about 2.3 is the smallest gap most people can see with the two colours side by side. Below that, your match is indistinguishable from the target.
One honest caveat. The sliders and the score are exact, but what you actually saw depends on your screen. Brightness, night mode, colour profile and viewing angle all shift the colours before they reach your eye. Your results are comparable to your own past runs on the same device; comparing across devices means less than it seems.
Reading a Delta E score
| ΔE | What you would see |
|---|---|
| Under 1 | No difference at all |
| 1 – 2.3 | Only visible to a trained eye |
| 2.3 – 5 | Just noticeable side by side |
| 5 – 10 | Clearly different, same colour family |
| 10 – 20 | Obviously a different shade |
| Over 20 | A different colour |
| Average ΔE over five swatches | Percentile |
|---|---|
| Over 20 | Bottom fifth |
| 13 – 20 | Below average |
| 8 – 13 | About average |
| 5 – 8 | Above average |
| 3 – 5 | Strong |
| Under 3 | Top few percent |
How to match more closely
- Set lightness first. Lightness is the dimension the eye judges most reliably. Get the two squares to the same brightness before touching hue or saturation, and the rest becomes much easier to see.
- Then hue, then saturation last. Hue errors are obvious once lightness matches. Saturation is the hardest to judge and the easiest to overshoot, so leave it until the other two are close.
- Overshoot deliberately, then come back. Sliding past the target and returning lets you see the match from both sides. Creeping up on it from one direction tends to stop early.
- Look at the boundary between the squares. The two swatches touch. If you can see a line where they meet, they differ. When the edge disappears, you are close.
- Rest your eyes between rounds. Staring at one colour for a while shifts your perception of it. A glance away resets your reference before the next swatch.
Frequently asked questions
What is Delta E?
A number describing how different two colours look. It is measured in CIELAB space, which is designed so that equal distances look roughly equally different. Around 2.3 is the threshold most people can detect side by side.
What is a good score?
An average under 8 over five swatches is above average. Under 5 is strong, and under 3 means your matches were essentially invisible next to the target.
Why are my results different on my phone and my laptop?
Because the screens show different colours. Brightness, colour profile and night mode all change what reaches your eye, so scores are only really comparable on the same device.
Why is there no daily version?
For the same reason. A daily only works if everyone attempts the same task, and two people on different screens are not seeing the same colour. It would be a comparison the game cannot honestly make.
Which Delta E formula is used?
CIE76, the straight-line distance in Lab. Newer formulas correct for some quirks in saturated blues and near-neutrals, but for matching by eye across the whole gamut the difference is small.