When you mix red and blue, you get purple; for a lighter shade, you just need white, which the icing itself would probably supply.
you start with white icing....... then add purple icing a little at a time...... to make purple, you mix red and blue. more red than blue though. If you use too much blue, it turns black......... now, the lilac icing will turn darker the longer it sits so you want to make it, ice the cake, then serve it right away....... It will turn the prettiest shade of dark purple the longer it sits.....
If you mix really light blue and pastel purple you get lilac.
You can only do this with paint but add white with purple
Lilac color paint is created by mixing purple and white. To achieve the desired shade, you can adjust the ratio of purple to white; adding more white will result in a lighter lilac, while more purple will create a deeper hue.
Blue and red make purple. Add white and you have lilac.
Lilac is a very light purple slightly tinged with blue. Mix (in paint) a tiny bit of crimson, a tiny bit of cerulean blue and massive amounts of white. It should yield lilac. Adjust the proportions until the colour is correct.
You can get lilac two ways. One, you can mix red and blue to get violet and then lighten to the shade of lilac with white. You can also eliminate some of the mixing by purchasing a violet or purple paint and then working with it and the white.
black, of course
Red and blue make purple, and as yellow is a light colour, i think that all of them mixed together would make a light purple, possibly a lilac.
Pink and purple mixed together can create a shade of violet or lavender, depending on the proportions of pink to purple.
Green
The colors teal and purple make a blueish gray color.
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.