Food coloring that you find at grocery stores typically comes in four colors: red, blue, yellow and green. Some stores carry larger lines of specialized shades, but most likely you'll have to mix colors to achieve the soft hues preferred for baking. These steps are focused on coloring icing or frosting; however, basic color-mixing theory carries over to many other projects in which you are coloring a white food. And speaking of icing, before you start mixing in the colors, you might want to pull out a few tablespoons to use later as a lightener in the event your color mix is darker than you had hoped.
Download a basic color wheel or color chart. Find one that shows both secondary and tertiary colors. You don't need this to follow the steps below, but it's a handy reference guide that will help you learn basic color theory — eventually, it will become second nature, and you won't need to consult a chart.
Obtain at minimum the following primary colors: blue, red and yellow. You cannot create these colors by mixing others, but with them you can create any of the other shades in the color wheel.
Mix equal parts of any two primary colors to produce the secondary colors of green, orange and violet. One drop of red mixed with one drop of yellow makes orange; one drop of yellow mixed with one drop of blue makes green; and one drop of blue mixed with one drop of red makes violet.
Create secondary colors by adding only one drop each of the two primary colors. Mix thoroughly. Continue to add more drops in equal amounts to achieve the color you want.
Use unequal amounts of primary colors to achieve tertiary shades shown in the outer ring of the color wheel. For instance, if your goal is to achieve a light orange, you would use more yellow than red, like one drop of red against two drops of yellow. After stirring, if you want to make the color darker, add more red; if you want it lighter, add more yellow or stir in more white icing.
Create some eye-catching tertiary colors using the following formulas:
Aquamarine = 2 drops of blue + 1 drop of green
Chartreuse = 1 drop of green + 1 drop of yellow Magenta = 2 drops of red + 1 drop of blue Gold = 3 drops of yellow + 1 drop of red
Try mixing colors separately for better results when creating pastels. For instance, to create lavender icing, start by adding a tiny swirl of red to create pink in one portion of white icing. Then add a drop of blue to separate portion of white icing. Combine small amounts of the blue icing with the pink icing to create lavender.
Fine-tune the color of the icing by making minor corrections. Make it darker by adding more of the darker primary color. Make it lighter by adding in some of the extra white icing.
Get black by mixing equal parts of all three primary colors. You may find that you will need to add more red, depending on the brand of food coloring you have. If a food coloring bottle doesn't come with a dropper, you can use a regular eye dropper, or you can use a straw. Hold the bottle at eye level and stick the straw into the bottle at a depth of no more than ¼ inch into the food coloring. Place your finger over the opposite end of the straw, pull the straw out, and move the straw to the icing. Release your finger to allow the captured food coloring to drip out.
Colors deepen with time, so mix your colors at least an hour prior to serving. Practice with small amounts of icing.