A LOT of red and a few drops of blue. Just add one drop of blue food coloring at one time and stir. Keep adding the blue one drop at a time till you the right shade of purple you are looking for.
by adding orange food coloring to white icing
You mix yellow and red food coloring. Add to your icing until you get the shade you want. More yellow will lighten the color and more red will darken the color.
The colours which are required to create green are blue and yellow, so technically you cannot create green from pink as pink is created from red and white, as adding blue and yellow to red would create brown or black. However, if you add a surplus amount of blue and green to pink icing, it should eventually become green if the amounts of blue and yellow out weight the amount of red dye used.
You should begin with a simple white icing. Then add two drops of yellow food coloring, and one drop of red food coloring. Mix it will. Add more yellow or red until you you get the desired coloring.
You must read the package as food coloring comes in different strengths depending on the brand. Though this answer is true it is not very helpful. a little more direction for Cake icing, for example, takes 3 drops of blue and 2 drops of green to create teal, a 3:2 ratio. Egg coloring takes 15 drops of blue and 5 drops of green, a 3:1 ratio (Reference 1). For teal, the general idea is to add more blue and less green. For orange, add more yellow and less red. For purple, use slightly more red than blue. Add a little bit of yellow to green to get a jungle green. Combine all the colors for dark brown or black.
food coloring
Using white icing you will have to add blue food coloring to it.
brown food coloring
physical change You are making a mixture of the icing and food coloring, which is a physical change.
Coloring causes only a physical change to icing because it does not alter the chemical characteristics of the icing.
you don't have to put water in food coloring you can put it in icing or cake batter
Use more food coloring