I'm making a cake as a surprise for my 12 year old in his school colors of royal blue and yellow. He plays basketball so I wanted it team colors. I just cannot get the color dark enough. I've added a ton of royal blue gel coloring but it is still probably medium shade. Any clue on how to get it dark enough??

all I can say is keep adding... When I do my colors, I try to stay away from the whole cake being a solid bright color, because you have to keep adding the coloring to get it dark enough. You could use white BC and then mix up a smaller batch using enough blue for dark blue and use for piping words, decorations, etc. Good LUck.
RItakk

Keep in mind that the color does usually get darker with time too

Like all intense colors (black, red, brown, & others) you really need to make these the night before wanting to use. It will darken with time & exposure to air.

Try adding some violet in with your blue. This will give you that deeper hue you are looking for and it will keep you from having to use SO much blue. Just don't add too much because it could end up all purple. I've had great success using the violet and royal blue icing colors together. Good luck!

I've also added a little black to deepen the blue.