How does viewing a film only in black and white positively affect your film viewing?

Well, there's one very important factor that black and white movies can teach you, if you select the right movies. Black and white films, done by good directors, can more easily show you the importance of light and shadow in creating mood, suspense, atmosphere and many other factors in creating the world of the film. Orson Wells was a master of light and shadow. Probably the greatest. Hitchcock was another. George Romero and his team making Night of the living dead also displayed a great mastery of light and shadow. Modern movies made in color often neglect this factor. Good directors don't, but there aren't that many good ones. Mario Bava was a master of light and shadow, and many of his lighting techniques are still in wide use today. Dario Argento is a master.

Many films, I think, are better in black and white. We would have no "film nois" without them.

so better.....