We all know about Mimes and the white make-up they wear, but how does the white face focus the performance? Think of this question too beyond the context of the silent mime but on any actor or performer who chooses to paint their face white.
First, it destroys all notions of individuality. Everyone's face becomes the same and instead of a group of individual actors, you suddenly have a group of mimes who are pretty much carbon copies. Even if every clown has a distinguishing mark in their make-up, it's not the same a different colored skin, unusually shaped noses, moles, or scars.
Now that we are not looking at the individual, we focus on what these faces are conveying. Movement and gesture become more specific. This is why mimes use the white face - they are substituting their words for their expressions. This is a double edged sword: now that we have this heightened focus, we as artists have to take responsibility to make sure that we are expressing is exactly what we are intending it too. Ambiguous expressions will confuse meaning in a world of black and white.
White face, unlike masks, is still a living expression. Masks do no move or contort to reflect how the character feels. Faces still are able to convey personality while still hiding the person.
Language and text becomes more powerful as well when an actor dons the make-up of a clown. The audience is given the clue that they are being asked to ignore the detail of the person's facial features and focus on other things. Just like performing a play with actor's dressed in black, white face causes the audience and actors alike to focus on the essentials of storytelling.