His 'Masquerade' costume is quite different from the musical. Erik (the Phantom) wears his signature mask throughout (except when Christine takes the mask off of his face) and his clothes are quite dark, which I think matches his mysterious character. A lot of costumes conveyed emotions well: when she is on the roof with Raoul during 'All I Ask Of You' she wears a red cape that matches the colour of the rose she is holding and then drops when she visits her father's grave she wears black and when she is in the opera 'Don Juan Triumphant' her costume is still simple but she wears a dark corset, and a red flower in her hair. The Opera costumes were wonderful - Christine's white gown for the song 'Think of Me' was very pretty and simple, and was a huge contrast from the previous scene where La Carlotta was wearing a fairly extravagant gown, and Christine was among the ballet girls, wearing a costume which showed a lot of skin.
It has made me want to look more at 1870s fashion, as I thought the costumes were lovely to look at, although some things didn't look quite right compared to others (not including the 'Masquerade' scene, I know that's meant to have a variety of styles).
I can't really talk much about the costumes as it isn't a time period I'm particularly familiar with. The costumes in this film were designed by Alexandra Byrne.