What is the significance of colors (such as red, violet, yellow, blue and green) as symbols of Paul's emotion?

The red carnation he wears takes on symbolic power for it indicates his defiance and a sense of importance he has about himself for someone so young.  The narrator describes it as a “dandyism,” which refers to a kind of pretentiousness.  His “white, blue-lined” face contributes to this sense of artificiality about him—he just doesn’t seen like a real boy. Cather uses color throughout the story to characterize his fantasy world, the world which he prefers and engages in at Carnegie Hall.  When he leaves, he wants to go with the soprano, and imagines “the green bottles in buckets of ice” as he stands in the rain thinking about this.  At home, however, he finds “horrible yellow wallpaper” in his bedroom, and considers his house ordinary and lacking in the sort of art he loves. He considers his life at Carnegie Hall wonderful, but he considers his home “a colorless mass of everyday existence.”