It not need to be so precise, even because it can change depending on color profile, but I would like to know if there is some formula/algorithm that receive the percentage of C, M, Y and K, then return true or false if it is rich black color.
for example C=70 M=60 Y=40 K=80 TRUE
and C=10 M=80 Y=100 K=85 FALSE
I need it to create an Illustrator script to replace the color of texts that is almost black (rich black) to only K.