I'm very new at this cake business and am having a great time but I have a question which I suspect has a fairly easy answer.
I'm making a sheet cake in white buttercream icing which will have a deep red and black border. How do I keep the dark colors from bleeding into the white. This cake needs to be made 2 days in advance, unfortunately.

Wilton recommends adding Meringue powder to the icing, 1 tablespoon per 3 cups of icing. This is suppose to help prevent the bleeding of colors. If you use a crusting buttercream it too should help.
Are you planning on refrigerating the cake??? If so it might have some condensation when you take it out. To help keep this to a minimum turn a fan on low, place it near the cake and let it blow on the icing until it comes back to room temp.

Thank you, Sandy1, I appreciate your quick response and will definately give it a try!!

You can also add White-White to your icing. This helps keep your color from going too far to the darkside and I've found that when I use it, I don't have a bleeding problem. I would say a Tbsn or two to a batch of icing.

What's white-white? I'm sorry,,but I'm interested b/c I add meringue powder to all my icings and it still bleeds..so I'd like to try the white-white instead if you can lead me to what that looks like please..thanks!

I'm familiar with white white, Wilton puts it out and it should be with the icing colors anywhere you find Wilton products. Let me clarify though, are you saying to use the white white in the white base icing and that will keep the dark colors from bleeding? Or are you saying to add it to the colored icing? Hope that doesn't sound like a really stupid question!

The only cake I have ever had to bleed was a white buttercream iced cake with black accents. This was also the only cake that I did not refrigerate but placed in a very cold room with a ceiling fan. Since then, all my cakes (I just do BC with fondant or BC accents) go into the refrigerator and I haven't had any more trouble. Everyone is different but I would say be sure you refrigerate it.

I made a white wedding cake with dark navy accents and was terrified it would bleed. As suggested on this website, I used Americolor brand food color and used a little meringue powder in the navy as well and I had NO bleeding.

You can also use milk instead of water in your BC. Even with milk, your BC still does not need refrigerating. I do not buy meringue powder unless I really have to. Milk is always on hand at my house.

Yes, you add the White-White to your icing when you make it. Not only does it make a really pretty icing, it does something to "block" the colors from bleeding. I also like to let my base icing set a bit before adding a darker color to it. This way it forms a nice crust that works as another barrier.

Thank you all so much for your help, I can see that this site is just what I need as I get started. Happy decorating everyone!!

Make sure that you have a good crust on your icing before you start adding the darker colors. If you can, let it sit for several hours, or even better- overnight.