Was there a black actor in Wizard of Oz?

The film started out in Black and white the ( reality) scenes at the farm and coming storm but somewhere en route to Oz- the film abruptly changed to technicolor- multic olor horses, and so on. This was unusual for the time and a neat trick. As many people are only familiar ( as I was) with the film on Black and White TV, this expanding trick was lost . As far as I know this was the only movie where they used this trick, as Technicolor was well-estabished in about l935 ( Elizabeth and Essex was in technicolor) and Oz came out in l939. so it goes.as paradoxically in a sense, Black and white is considered morfe ( realistic, newspaper-like) also having arguably a greater usable shelf-life, it was used almost exculsively on US movie filmed during the War / (l94l-45) with some exceptions. The Oz film was made in l939.