I am attempting to make navy blue colored icing. I just can't get it there. I had a light shade of blue left over using royal blue wilton color. Then I added some white b/c i needed more icing and then i added black and a lot of royal blue and i have a greyish/teal color. The cake i am doing is light blue with navy pin stripes and a navy blue monogram. HELP! Thanks

I googled it and :
1 Sky Blue + 1 Violet gives you navy blue

thank you so much. i googled too and i never found that. all i could find is powder blue and royal blue. i appreciate your help.