Whenever I color gumpaste and it dries, it is so much lighter than the original color. I just tried using about 1/3 gumpaste to 2/3 fondant in peach. Nice color when I started. After it fully dried, it was so pale. How do you keep the vibrant color when using Wilton gumpaste?
Personally I like the Satin Ice Gumpaste. I haven't had a problem with fading colour
Have you ever tried Tylose powder? I add that to my Satin Ice Fondant and have never had an issue with my colors fading. Good luck!
Some colors just fade more than others. If you use powdered food coloring they tend to fade less. I love the Crystal Colros powders that you can get from Sugarpaste.com, they're strong color and they don't fade. http://acaketorememberva.blogspot.com/2010/01/interview-beth-parvu-on-crystal-colors.html