AtlasVisionColour vision check

A screen check, not a diagnosis

Color blind test: red-green and blue-yellow plates

A color blind test: 24 original dot plates, with control plates for your screen. Nothing is saved.

  • Full brightness
  • Night Shift/True Tone/blue-light filter off
  • No “vivid” display mode

24 plates · pick the digit you see, or Nothing / not sure · no timer

  • 24 dot plates
  • About 3 minutes
  • No ads
  • Nothing saved

Before you start

  • Turn the screen brightness up.
  • Turn off Night Shift, True Tone, Night Light, blue-light filters, colour filters and dark-mode colour inversion.
  • Take off tinted glasses or coloured lenses; ordinary glasses are fine.
  • Use ordinary indoor light, not a dark room or direct sun on the screen.
  • Switch a phone or monitor out of “vivid”, “saturated” or similar display modes; those modes, and some Android screens without colour management, can make a hidden digit visible.
  • Hold a phone at a comfortable reading distance; on a computer, sit about an arm’s length away.

These are things to do, not something the page measures: nothing here adjusts the plates to your screen.

No result from this check is saved: not in this browser’s storage, not on our servers and not in an account, and there is no Save button. Our self-hosted counter records only that a check started and that it finished, as two event names, never which plates you read or what the check found.

How this check works

What the plates are

Each plate is a circle of dots in two colours that sit on one confusion line: a straight line of colours that people with one kind of dichromatic colour vision cannot tell apart. Every dot takes one of five brightness steps, in equal areas inside and outside the digit, and the two colours are balanced in brightness as a simulated dichromat sees them, so the plates are designed for colour, not brightness, to carry the digit. Of the 14 red-green plates are designed to hide their digit from red-green colour vision differences; the 7 blue-yellow plates are designed to hide it from the blue-yellow kind, and the 3 control plates differ in brightness too, so everyone should read them.

The plates were made for this site and are the same for everyone, in the same order. Before they were published, each one was checked with a published simulation of dichromatic colour vision: the digit had to disappear for the kind of colour vision the plate is for and stay clear for typical colour vision.

What the result can and cannot say

Most colour vision differences are milder forms, and in a simulation of the milder forms these plates mostly stay readable, so a screen check like this one finds the stronger differences and can miss a milder one. The result names a pattern: none seen, likely red-green, likely blue-yellow, or that your screen or settings cannot show the check. It gives no score, no strength and no type within red-green, because a screen cannot measure them honestly. Screens differ in colour, settings and filters change it, and the light in the room matters, so the check can be wrong in both directions, and the risky direction is a pass.

Sources

Questions people ask

Can an online color blind test diagnose color blindness?

No. A screen cannot show exact colours: brightness, settings, filters and the light in the room all change them. An online check can suggest a pattern worth asking about; an eye-care professional with plates under proper light, and other tests if needed, can tell you whether you have a colour vision difference and which kind.

Is this the Ishihara test?

No. The Ishihara plates are a printed book, and this page does not use them. These plates were made for this site from published colour science, with control plates that everyone should read, and they include blue-yellow plates, which the Ishihara book does not.

What are the control plates for?

Three plates differ in brightness as well as colour, so anyone should read them, whatever their colour vision. One miss is taken as a slip and the check carries on; if two of them do not come through, the check stops and says your screen or settings cannot show it, instead of naming a pattern.

Why does it not tell me how strong my color blindness is?

A screen cannot measure that honestly, and a number would look more precise than it is. The check only says which pattern your answers fit, and an eye-care professional can measure the rest.

Is my result saved?

No. Your answers and the result stay on this page while it is open and are never written to the browser, sent to us or kept in an account. Leaving or reloading the page clears them.