Firstly, I created a simple sketch that creates ‘Ishihara colour plates’. These are used to test people to see if they are colour blind. You can see the sketch here. The sketch takes an image, loops through every ten pixels and based on the colours of the image it places a coloured circle. The colours are various shades of orangey-brown or green. The shades are designed to be visible to most people but not to people that have Deuteranopia, Protonopia or Achromatopsia. The first image on the right is the result of putting this image through the sketch.
If you can’t see a slightly distorted disturb logo in green in the image, then I am afraid that you might well be colour blind.
Being able to test colour blindness is nice and all, but what if you want to see what it would be like to be colour blind? The second sketch I created takes various images and applies filters on them to re-create how people with various types of colour blindness see. You can see the sketch here. NOTE: This sketch is best viewed in Chrome or Safari - It is very slow in Firefox.
If you press 4 on the sketch, you can see another Ishihara colour plate that I generated using my first sketch. If you view the colour plate normally, you can see the letters “LOL WTF”. If you switch to other types of colour blindness, you can see how someone that is colour blind would see the colour plate.
You can see demos and the full sources here;