A basic box of food coloring includes red, green, yellow and blue and can be mixed together with a clear or pure white base to make thousands of colors and hues. Color mixes are typically measured in drops of each color used, with more of a particular color deepening the impact of that color. Pure white frosting is best for adding food color to create a colorful frosting. Frosting with vanilla or other flavors can impact the final color.
Food color charts and mixing guides are available from sites such as FoodNetwork.com and BettyCrocker.com. These sites provide color samples and mix ratios for blending food colors. Color blends such as carrot cake, made with 50 drops of red and 40 drops of yellow, and watermelon, made with 46 drops of blue and 78 drops of green, are designed to color a single can of white frosting. One-hundred drops of food coloring is equal to about 1 teaspoon.
Gourmet food dyes and colorings such as those sold by Wilton.com come in a wider array of colors to create unique color blends and speciality colors. These food coloring options can be used to create colors such as hunter green, sky blue, lavender, mauve and avocado. These food colorings are typically in single bottles and are not mixed and measured in drops.