For some reason, when I first read The Road to Oz, I thought Polychrome would be dressed in purple. But when I finally saw color pictures of Polychrome later, she was dressed in all colors of the rainbow or plain white.
Polychrome isn't a very deep character. She is one of the Rainbow's Daughters, who dance upon the Rainbow when it appears after a shower.
Polychrome appears in four books by L. Frank Baum, The Road to Oz, Sky Island, Tik-Tok of Oz, and The Tin Woodman of Oz.
She's also a character who hasn't appeared in many Oz adaptations. She was played by Dolly Castles in the play The Tik-Tok Man of Oz, which served as the basis for Tik-Tok of Oz. A rainbow-colored girl who was labeled as Polychrome can be seen in the famous crowd scene of Disney's Return to Oz. (I thought she looked more like Fredrick Richardson's Queen Lulea in Queen Zixi of Ix.) And in The Oz Kids: Christmas in Oz, she flies across the sky with her own daughters. With the exception of the first one, her appearances have mainly been cameos.
Even though she is a simple character, she is a rather popular one. She is probably the closest to the stereotypical fairy that Baum ever got. Her life away from the earth almost makes her feel like an angel.
Polly (as Dorothy calls her in The Road to Oz) seems to be a rather careless sky fairy, as she falls off of the rainbow several times. Her life's purpose consists of dancing on the Rainbow, and when she's on earth, she does so to keep warm.
Her diet consists of things we don't eat, such as dewdrops, mist-cakes, and cloud-buns. When she is offered regular food, Dorothy notes she only eats as much as a fly. Either Baum is saying that Polly is built very different from humans (and much lighter), or she has a terrible eating disorder. (I'll go with the former.)
A little oddity I found when re-reading some of the Oz books recently was that in The Road to Oz, Polly says she does not know how to do magic, explaining "We who live on the rainbow among the fleecy clouds have no use for magic." But later, in The Tin Woodman of Oz, she is able to. While she can't undo the transformations of Mrs. Yoop, she manages to prepare magic meals, removes Tommy Kwikstep's additional legs (and his corns), straightens out dents that befall the Tin Woodman and Captain Fyter, and changes the size of herself and the entire group so they can walk through a burrow made by a rabbit.
I would call this an inconsistency if it were not for the length of time between Road and Tin Woodman. In between them is her appearance in Tik-Tok of Oz, in which some of her friends fall under transformations or other magical traps. Seeing as she has no way to assist, it is possible that she decided to learn some magic so if she was in such a situation, she could help.
I'm not forgetting Polly's appearance in Sky Island, where she is reunited with Button-Bright and meets Trot and Cap'n Bill, but her appearance is little more than an extended cameo, where she seriously helps out by looking up a law. Yep, she appears just for legal advice.
Polly is a great character! She might be a little too quick to make friends, but she certainly manages to ally herself with our heroes consistently. Her beautiful character was yet another wonderful addition to the long list of Oz characters.
(Okay, that takes care of Button-Bright and Polychrome, now to do one for the Shaggy Man.)