1. A method of converting a digital colour image having colour values to a digital colour image with improved colour distinction for an observer suffering from a type of colour-blindness, wherein the digital colour image with improved colour distinction is having converted colour values, the method comprising the steps of: defining a number of main colour values of the digital colour image; converting the main colour values to converted main colour values such that the converted main colour values are perceived as distinguishable from each other by said observer; and rendering the digital colour image with the converted main colour values.