Colors will change over time; fading in the light (if you have florescent bulbs, or in daylight); I see the most color changes with purples, blues and some browns. I personally prefer Sugarflair colors which I get from Canada; but I also use AmeriColor and Chefmaster colors. Sometimes I will use a pre-colored fondant from Satin Ice added to white to get the color I need. Last year, I did a painted stained glass cake, and the colors I used were purple, violet and grape - these were airbrush colors because I was painting on fondant and wanted it to dry. In less than 5 hours, the colors had faded and the purples became blue (I showed the client photos I had taken when I first finished painting and then the ones when I delivered the cake. The photographer’s photos taken 4 hours after delivery (this was during the hurricane last August and they let the vendors deliver early so we could avoid the worst of the storm) show the purples as blue.) I emailed the manufacturer and was told that colors fade when exposed to light, and faster when exposed to florescent lights (and, my colored sprinkles that we use to make our version of funfetti, prove this point. The side of the plastic bin that faces the front of the shelving exposed to the light is faded, while the sprinkles on the opposite site which is on the inside of the shelving, are still bright).