download iExpressions at
https://aescripts.com/iexpressions/
In this tutorial you learn how to link many color properties to a slider such that they can all be changed at once. You just need to specify for each color property which color it should have for the minimum and the maximum value of the slider. When the slider is moved, the colors then blend between these two extreme values.
As an example, we control the hair color, skin color, eye color etc. of a character by linking them all to a slider.
