Making purple food coloring without using red can be difficult, because purple is the direct result of mixing the primary colors red and blue. However, there are two ways you can achieve this effect. One is by blending blue and pink food coloring together (since pink is a derivative of red) and another is by using the juice from blueberries and food coloring.
Making Purple With Food Coloring
Gently squeeze 35 drops of pink food coloring into the food you want to color. You must count each drop, instead of estimating how much you added; otherwise you won't achieve the color you want.
Add 25 drops of blue food coloring to the food. Count the blue food coloring drops, as you did the pink ones.
Mix the food with a spoon until the food coloring is evenly blended into it. If the food looks too pink, add another four drops of blue food coloring and mix it again. If the food is too blue, add four more drops of pink coloring.
Making Purple With Food Coloring and Blueberries
Juice 2 cups of blueberries in a juicer. The juice produced will be pinkish-red.
Dip a plastic dropper into the blueberry juice and fill the dropper with juice.
Carefully squeeze 35 drops of the blueberry juice into the food you're coloring. Count each drop individually.
Squeeze 25 individual drops of blue food coloring into the food.
Blend the food together with a spoon until the purple is evenly distributed. Add a few more drops of blueberry juice if the color is too blue. Add a few more drops of blue food coloring is the food looks too red.