Web design: color multiplication

Self-tutoring about color multiplication: the tutor looks at a method.

A way to define multiplication of two colors rgb(Ar,Ag,Ab)and rgb(Br,Bg,Bb) is rgb(Ar*Br/255,Ag*Bg/255,Ab*Bb/255).

For example rgb(100,100,100)*rgb(100,0,100)=rgb(39,0,39), seen as

color1*color2=color3

stackoverflow.com

lesscss.org