 One of the reasons Alfred Hitchcock (I) (qv) shot the movie in  black and white was he thought it would be too gory in color. But  the main reason was that he wanted to make the film as inexpensively  as possible (under $1 million). He also wondered if so many bad,  inexpensively made, b/w "B" movies did so well at the box office,  what would happen if a really good, inexpensively made, b/w movie  was made.