What’s your colour discrimination number?
https://www.keithcirkel.co.uk/whats-my-jnd/
Find your Just Noticeable Difference in colour perception. How small a colour difference can you actually see?
@falcennial @shaungriffith
try 'hard mode'
https://www.keithcirkel.co.uk/whats-my-jnd-hard/
Hard mode: find the odd square out of nine. No gradient hints, just raw colour perception.