A rundown of the costumes Elphaba wears in the musical.
Her Shiz Uniform is navy, in direct contrast to Galinda's cream.
On her First Day, she wears a navy blazer with black (or maybe a darker navy?) piping over a pleated dress and a dickey. She also wears a knitted cap.
Shiz Uniform article (coming soon!)Shiz Uniform Gallery
For the Ball, she takes off the dickey and blazer, and adds the hat Galinda gives her.
After becoming "Galindafied", she wears a different blazer (presumably of Galinda's) which is highnecked, form-fitting, and mutton-sleeves.
When she goes to the Emerald City, she wears a very Victorian black gown. It has a mandarin collar, mutton-sleeves, a light, swishy skirt, and a pointed waist with buttons to the neck. She also wears the hat, and during Defying Gravity, Glinda gives her a black cloak, she magics a broom, and presto! becomes the "Wicked Witch" we all know and love.
Emerald City Dress ArticleEmerald City Dress Photo Gallery
During Act 2, she wears the same dress as before, only, due to her rampaging across the country saving animals she's never even met, it's ripped, patched, and turned on itself--Susan Hilferty says there are 14 different fabrics, which is 5 more than Galinda's bubble gown. I also heard a rumour that it weighs 95 pounds and that Shoshana Bean lost 45 pounds while playing Elphaba... but who knows whether these are true.
Act 2 Gown Article (coming soon!)Act 2 Gown Photo Gallery