Color Oracle

color oracle logo - colour chartColorOracle is a free programme that simulates the visual appearance of documents for different types of colour vision deficiency.

Colour blindness (colour vision deficiency, or CVD) affects approximately 1 in 12 men (8%) and 1 in 200 women in the world. In Britain this means that there are approximately 2.7 million colour blind people (about 4.5% of the entire population), most of whom are male.

There are three forms:

  • protanomaly, which is a reduced sensitivity to red light,
  • deuteranomaly which is a reduced sensitivity to green light – the most common form of colour blindness
  • and the rarest, tritanomaly which is a reduced sensitivity to blue light.

In the past it has been difficult to appreciate the impact of your colour choices when creating web pages, diagrams, maps, etc. Whilst there were some sites that you could upload documents too, not all formats were supported and the process was cumbersome. Color Oracle changes all that. When the app is running you can toggle between four modes:

  1. Normal Vision
  2. Deuteranopia
  3. Protanopia
  4. Tritanopia

Changing modes remaps the colour gamut of your display, meaning that everything you can see on the screen adopts the selected colour sensitivity.

This colour blindness simulator takes the guesswork out of designing for colour blindness by showing you in real time what people with common colour vision impairments will see. It makes it easy to check that the documents you are creating use colours which are easily distinguishable to everyone looking at them – supporting Universal Design principles. It also helps you check the suitability of materials prepared by others.


Available for computers running Mac OSX, Windows and Linux.
The software can be downloaded for free from this website:
We are investigating whether we can get it installed to the University managed desktop computers.

This should be installed on everyone’s computer. It’s free and works well – what’s not too like about that?

Things to Watch
In general the tool performs very well. At the time of the review the authors acknowledge that highly saturated colours may not be simulated as well as the others – though they are working on this.

More details are available from this website:

REVIEW DATE: February 2016
PRODUCT: Mac OS Version 1.1.4