Rather, it is specifically the rejection of the star concept and the casual mixing of professionals and of those who just act occasionally. It is important to avoid casting the professional in the roll for which he is known. (Bazin "Part 2" 23)
While an accepted star is received everywhere as himself, the success of a film is apt to identify the ordinary actor with the role he plays in it. Producers are only too glad to repeat a success by carpeting to well-known public fondness for seeing their favorite actors on their established roles. And even if an actor has sense enough to avoid being confined to a single role, it is still a fact his face and some recurring mannerism in his acting having become familiar will prevent the amalgam with non professionals taking place. (Bazin "Part 2" 25)
One of Bazin's central concepts of Neorealism is this "law of amalgam". It's essentially staying the idea of typecast: as an actor takes roles, he amalgamates rules to his person so every role he takes is necessarily informed by those of his past. Never can he purely play a role, his past is always with him.
Each image being on its own just a fragment of reality existing before any meanings, the entire surface of the scene should manifest an equal concrete density. Once again w have here the opposite of the "door-knob" type of scene, in whixh the color of the enamel, the dirt marks at the level of the hand, the shine of metal, the warm away loom are just sonny useless facts. (Bazin "Part 2" 37-38)
Bazin's "image fact" seems remarkably similar to eisenstein's concept of "attractions", elements of the scene which, in Eisenstein's world, relate to create meaning. It seems Bazin agrees; however, his conception of the proper relationship between the facts is closer to epic rather than conflicting.