I want to use red frosting for a fourth of July cake, but it always bleeds into my white frosting. Have any ideas on how to prevent this.
Do you use a crusting icing? If so, let one of them crust before you add the 2nd color. I can't recall the last time I had any bleeding.
As we learned in science class, water will find the fastest, easiest path to anywhere (how caves are formed). Moisture on moisture will blend together, with each of the moistures (aka icing colors) finding the fastest, easiest path to anywhere. Pour a glass of red Kool-Aid and a glass of yellow Kool-Aid on your counter and watch them blend into orange.
When you apply "wet" icing onto "dry" (crusted) icing, the wet has no where to go ... it can't soak into the dry barrier of the crust. Just like if you pour green Kool-Aid on your hard counter top ... it stays green. It doesn't blend with anything.