I have problems with not getting red and black out of my buttercream frosting, they turn out pink and grey Any tips would be very much appreciated as I have a cake next week I will need to know.
I also wondered how do I get a tan/skin color? I have no idea what colors to mix for it?!

Have you tried the americolor super black and super red gel colors? They're amazing. super concentrated so you don't have to use as much gel to achieve the color you want. Also, make them a day ahead of time, the color will intensify. And for black BC, if you start with chocolate BC (if possible) you will use even less black gel. For tan, they actually make flesh tone gel color or you can use a tiny amount of brown, depending on the shade. I see you're form Tonawanda, you can get the americolors at a bakery supply shop on Williams so you don't have to order online

I did actually just buy those but haven't used them yet. I'm glad to hear that they are more concentrated and should be better. I don't have chocolate BC but could I simply add a little cocoa powder and confectioner's sugar to it?

Yes, I make my own chocolate BC using cocoa powder... my personal fave is hershey's special dark cocoa powder (which I find at Wegmans on NF Blvd) Gives a super yummy flavor and a nice dark brown color to start with so you only use a little black gel color.

Wilton's BC is terrible in my opinion, esp the all shortening one. yuck. I use an all butter BC most of the time, but if it's really warm (which doesn't happen all that often around here) I will use 1/4 of shortening (not crisco) to give it stability if I HAVE to. Everyone ends up having a BC recipe they swear by, and it's always different from the next baker's. I dont use a crusting BC if that helps... If I were you Id experiment. Start with 2 sticks of unsalted butter, cream in a tsp of real vanilla, and a pinch of salt and add powdered sugar a cup at a time until you like the taste. Add more flavoring if you'd like. Keep track of what you add, so you'll know how much of everything you need the next time you make it. You can make a half batch or even a quadruple batch depending what you need once you have a solid recipe you like. I think mine with heavy cream, but you can also use milk or water, depending on your needs. Same idea with chocolate BC (or any other kind) just keep adding til you like that taste. That's how I learned. And I cream mine for a while in my KA so it's nice and smooth!