I made my first fondant cake on Friday. It was a pillow cake for my sister's birthday. (It's in my pictures) When I made it it was purple. When I gave it to her it was blue! I have never used fondant before and have no idea how it works. Is that normal?? What do I have to do so it keeps its color? 
Adding more color won't stop the color change--the change is due to a reaction between the light and the type of pigments used by the manufacturer to create the color. Wilton colors--pinks, purples, and blues, seem to fade/change more than Americolors. The changing can also be affected by the type of fats and amount of water you use in your icing (buttercream) and the brand of fondant you choose.
You can slow the change by covering the cake in blue or black garbage bags and keeping it out of the light--especially fluorescent lights-- but if it sits out at a venue in bright light, it will still change color. Sometimes the only way to get around it is to airbrush on the color if it's a shade prone to changing or fading.
Rae
Thank you for the thorough reply. I will try and cover it next time, and have been meaning to buy americolor for a while. I appreciate the response 
Quote by @%username% on %date%
%body%