[jansan]

Years ago I was in contact with a person with total color blindness (https://en.wikipedia.org/wiki/Achromatopsia) and together we developed a filter to simulate this. It never went online, but if I find that project on my backups, would you be interested in the parameters of the filter? I could just post it as an issue.

The idea at that time was to help web developers avoid color combinations that are really hard to read for people with achromatopsia. But we soon found out that the worst color combinations were basically a total eye sore for people with normal color vision, so the benefit was limited.