I need to write with black icing on fondant. The problem I encountered was after about 4 hours there was a shadow of a gray/purple color from the icing on the fondant. Is there anyway to prevent this? I used Wilton coloring. Would another brand work better?

I was recently advised by another CC member to add a tablespoon of meringue powder to your icing to stop bleeding of dark colours.

I have also been told that Americolor doesn't run as bad as Wilton's.