Digital BW, The Print

Hi everyone,
I'm curious what kind of Math is behind curves blending process? - Specifically if I want mathematically build smooth transition between let's say Black, Light Black and Light Light Black inks - what kind of variables are necessary (I assume density and Lab values) - and what equations to use to build the curves? I've had hard time finding any info online - if anyone can point me to a right direction or share this info it would greatly appreciated

Thank you very much in advance

Eugene