I have a castle cake due on Sunday and made the towers for it this weekend so they would nice and dry. I made them out of gumpaste that I colored a light pink. After drying overnight, in what I thought was a dark room, the towers are now almost white again....someone turned on the lights!!! Now I have to redo them which is not a big deal but is there any other way to keep this from happening short of making certain they are not exposed to flourescent lights? Just wondering so I don't waste my time and gumpaste again this week. Thanks in advance.

Here are some ideas.
Keep the cake lightly covered with a dark plastic bag to keep the light off. Store it in a dark room.
Dust the pink with dusting powder.
Start with a darker pink.
For purple - add 1 tsp baking soda to 1 lb fondant or gumpaste. It will help to preserve the colour. I tried this with pink and I think it also works.

Last month I made extra leaves from gumpaste, and stored them in tupperware in a cupboard. No light. I opened them this week, and they are all lighter. I have NO idea why these buggers would fade.