I have been adding black gel to white fondant trying to get grey. But all I can get is purple! What's going on? How can I make grey?

I follow the advice of this color chart and add blue. I've not tried it with fondant, only cookie icing, but it works!

http://cakecentral.com/gallery/858073

Color your white fondant with any 2 or 3 dark colors first, then add black coloring to turn it black.

Use THAT black fondant + white fondant to make gray and it'll stay gray!

I just did it this way myself...I started with white fondant, added a small amount of brown, dk. green, and navy blue coloring...then I added black and let it rest.

I mixed some of that concoction w/ white fondant and made a perfectly gray colored pencil (for a drawing pad cake).

FlourPots, that was my first attempt. I added already black fondant to white fondant, but it turned out more brown than grey. Probably because I make my black fondant by starting off with chocolate pettinice and adding black colour.

In the end I found a website which said that any two complementary colours mixed together will make grey. Such as orange & blue, purple and yellow. So since my icing was already purple, I added some yellow. And wouldn't you know it, I actually got grey..... who would have thunk it!

Yep, that's what I was going to say - yellow is the key!