What it does
Color Oracle is a free colour-vision simulator for Windows, Mac and Linux. It filters the entire screen independently of the design application. Windows and Linux builds require Java.
Choose Deuteranopia, Protanopia or Tritanopia from the Windows taskbar icon or Mac menu bar. Grayscale offers a separate luminance view. A mouse click or keypress returns the screen to normal. This makes it useful for checking a map or dashboard spread across several windows.
On Mac, preferences assign function-key shortcuts, and Save Filtered Screen Image writes the simulated view as a TIFF. The information panel can be moved and resized.
The published release dates from 2018. Its Mac manual documents a screen-recording permission requirement on Catalina, and its Windows guide lists systems through Windows 10. These older requirements deserve a compatibility check before installation on a newer workstation.
Strengths
- A full-screen preview works across different applications.
- The Mac version can save a simulated screen as TIFF.
Watch out for
- Windows and Linux need Java.
- The published release and platform guidance are older.
Best for
- Reviewing colour distinctions across a complete desktop design
Sources
- Color Oracle overview and downloads (Oct 27, 2026)
- Color Oracle Windows manual (Oct 27, 2026)
- Color Oracle Mac manual (Oct 27, 2026)