I made my buttercream last night and adding the coloring to let it sit over night. I HATE red and black. My black is an ugly dark gray. I even used an entire thing of coloring. I have been told it will darken over time but it's still as ugly as it was last night. My red is ok but not as red as I had hoped it would be. I guess today I'm going to hobby lobby to buy already colored icing because I don't have time to start over. Ugh...this cake has been a pain in my a$$ since the beginning.
It all depends on what coloring brand you used.Wilton will take you at least a bottle of each color to get a good black and red.Try using Americolor gel pastes or Chefmaster.It is too late to get those now but buy more Wilton if that's all they have.Add a touch of yellow to brighten your red..not alot though or it goes orange.Black you have to keep adding.