Ok, I used black icing for my over the hill cake. I got it black and looking great. I decided to used some piping gel in my black icing to do my lettering. BIG MISTAKE!!! Apparently, by adding piping gel, the black will bleed. So upon delivery, my message was a little purple around the black lettering. Anyone else make this mistake? The border was fine, but it had no piping gel in it. So I'm assuming that's the culprit!! Now I know. It actually worked out fine, it almost looked as if I were going for some special affect in the lettering...lol
Thanks mmdd. I had an order (from the same person) for 3 different cakes. The basket cake, the over the hill cake and the princess cake. The order came in late Tuesday night and had to be ready by Friday for delivery. What a deadline. Atleast now I know I can work under pressure. 
Black bleeds whether you add piping gel to it or not.
But -- I have read on other forums in the past that if you put piping gel down as a barrier between the BC and the black icing, it will prevent it from bleeding into the BC.
Theresa 
I just learned this from my cake class if you add a tablespoon of cornstarch per cup of bc icing your deep colors should not bleed I did it in my clown cake the red,blue and green didn't bleed!1 i guess it works! May be try that nest time no piping gel i don't know if that did it though
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