Why, in the other world, were Ms. Spink and Forcible's button eyes white instead of black like everyone else's?

Question

In the movie Coraline, when Coraline goes to the other world and visits Ms. Spink and Forcible, their buttons are white instead of black, like everyone else's.

But during the show, they come out of their costumes, their eyes are suddenly black.

Does this have a meaning, or does it just look better?

Answer 1

They were putting up a show of friendliness for Coraline the first time. They wore a costume, a mask needed for such performance. White eyes not only look better, but are symbolizing reveal, the change from white to black symbolizes masks falling down.