Obviously this is not actually a Renaissance Festival work uniform! This is one of two spring/summer dresses I made last year.
This one I made for Easter.
It's a little hard to tell, but the top and skirt are made of plain white cotton, but the waist and shoulders are of a gauzy, white silk-like fabric. Up close, it shimmers a bit, but this did not come through so well.
FAQ: The pattern is McCall's M5094.