Color bleed with black outline

You should outline directly on your cookie, so the outline rest on the surface of your cookie and seals it to prevent the spill.  Somethimes in edges of the cookies there are small cracks, seal it before you fill the cookie. You don't need to wait to many time to dry the outline, it is dry when you end of outline all your other cookies, but if the weather is wet, you need to wait . 

You can outline and fill in waxed paper, but cookies are not exactly flat, I use it only for small ornaments not the whole cookie. 

Not all of us can pay for a Kopycake, but there is a how to do one for yourself in web using only a  batery lamp, boxes and a piece of glass or something transparent.  I used cardboard to build stamps to "draw" what I wanted to outline on the cookie. I use as ink watered royalicing to "print".  You can use comercial stamps using endible paints for that too! Or cutters...

On a class I took they teach me to make many copies of the picture as needed, cut the outline, cut each individual piece alone and outline with a tooth pick (for cakes), but in cookies you can use a edible marker. 

I hope I could help you.  I'm not profesional, only a hobbie Baker (for birthdays and other family special dates and holidays).

I like to make sure black is completely dry before flooding with lighter colors, as bleeding is typically a crap shoot. I usually wait several hours (4 hours would be fine here, except possibly on very humid days or if my outlining icing were somewhat loose to start). I also like to push the lighter flooding colors to the thickest possible consistency, because the thicker the icing, the faster the icing dries. Even if you've completely dried the black, a wet icing sitting next to it for too long can dissolve the black and lead to bleeding. You can accelerate the drying time in a dehydrator (or near a fan), both once you've laid the black and again after you've filled it.

I second what Julia says. I allow my black to thoroughly dry, use as thick of an RI as possible for the fill and then it goes right into the dehydrator or in front of a fan. Exactly the same. The only thing that I can add is that I try not to over-saturate my black RI with the black gel color.  Depending upon the base cookie flavor, I will start with untinted RI, add a bit of dark cocoa powder to give it some color and then add my black.  I mix the black tone lighter than I need and let it sit a day or even two for the color to deepen, and intensify. This allows me to use less black and I think that it helps me for the bleed aspect.  At least that is my supposition.  If my base cookie flavor should not have a hint of cocoa taste with it, I just leave out the cocoa powder.  If you do use it, don't use too much as it can affect the workability of your RI if you overdo it.  Use just enough to give some color before adding the black.  On this end, I happen to use Americolor Super Black, but have been hearing good things about Chef Masters colors as well. I think that is what Julia uses.  

Yeah, you know, I've never had trouble getting a very black black with Chefmaster. I don't let it sit to intensify either. I just use a healthy squeeze or two depending on the quantity of icing. It starts gray, or course, but when it turns a telltale dark shade or gray or light black, that's when I stop adding color, because it darkens a lot upon drying.

Thank you for the advice - it is much appreciated, and all sounds great.

Thanks, Julia! I will try Chefmaster!