[yt-users] rainbow+white?

Hi yt-users, I am imagining that this is something silly, but I tried to use rainbow + white, and it seems to me that it is actually rainbow + black? Certainly on the colormaps page those two maps look identical: http://yt-project.org/docs/dev/visualizing/colormaps/index.html?highlight=cm... Is this actually the case? is there just some simple pointer that is messed up somewhere? Or can someone point me to the white in rainbow+white? Thanks! Stephanie