Recolor an element after applying an effect in Illustrator

Question

I want to change the colors (kind of recolor) of an element A on which I apply an effect E(x), such that the new colors will be based on the colors of the element after the effect B=E(A). Does anyone know how to do it?

For example, let's consider a color gradient on which we apply a stamp effect. This last one will turn all the colors to black and white. Now I want to change the black to blue and the white to yellow, but if I apply recolor on the original object I will always get a black and white output. Instead, I want to change the colors after the effect.

Answer 1

This will only work if the result of your effect is a black and white image like the stamp effect gives you (or the halftone effect in this case).

Original object:

Halftone effect applied:

Create a blue rectangle underneath your black and white object. Select both, open the transparency panel and click "Make Mask". This will create an opacity mask from the black and white object:

Add another rectangle below to color the white (now transparent) areas:

This is more of a workaround though. There's no easy way to recolor objects based on the result of effects.