This new web game tests your eye’s color accuracy (and your screen’s)

Not all screens and monitors are built to the same standards for depth and color accuracy, and your eyes have their limits too. Now you can find out how well you (and your devices) can distinguish colors, potentially for bragging rights.

Software developer Keith Cirkel created the app “Your ΔE(OK) JND?” » website, allowing you to determine the Delta-E (ΔE) of your just noticeable difference (JND), using the Oklab color space supported in modern browsers. In other words, you get a score based on your ability to distinguish one color from the other color, with around 40 rounds of testing. Simply find and click/tap the line between the two colors on the screen.

Although this is primarily a human eye test, with most people scoring around 0.02 in the Oklab color space, your equipment matters too. If you have a phone with a low-end display panel or a budget gaming monitor with terrible color calibration, you’ll likely get worse scores. Increasing the brightness might also help you get the best results. The more decimal points, the better.

I got a score of 0.0051 on my iPhone 15 with its OLED display, and a score of 0.0058 on my MacBook Pro 2024 with its Liquid Retina XDR display. Other people here at Practical geek also noticed different results between devices. Your final score can be easily sent to others with a personalized URL, as proof of your superior or inferior field of view.

Cirkel created the website while working on a CSS color minifier, where it was important to know how many decimal points could realistically be removed from color values. He explained in a blog post: “A color like oklch(0.659432 0.304219 234.75238) unnecessarily precise? Spoiler alert: yes. I argue that you almost never need more than 3 decimal places. For oklch and oklab this is a safe cap, and for their less than decent variants (lab & lch) you can get away with even less. Writing more is just wasting bytes.

The blog post (linked below) goes into much more detail about the science behind the test, including how Delta-E maps to different color spaces and how web browsers calculate color values. Crikel also noted that the website produces higher just-noticeable-difference scores than real-world scenarios: Outside of gamified tests like this, most people don’t look closely at their screens to check color matching.

Source: Keith Cirkel