For her vibrant red hair Rhianna uses her own "secret" blend of Manic Panic colors. I don't know if this is already a known thing or not; I've seen a few posts of people wanting her hair color, so I thought I'd share.
http://www.manicpanic.com/images2/press/articles/web_rihanna_vogue.gif
I suspected that this is what she used, I love Manic Panic.
Sent from my iPad
http://www.manicpanic.com/images2/press/articles/web_rihanna_vogue.gif
I suspected that this is what she used, I love Manic Panic.
Sent from my iPad