I will be making a cake that will use maroon and a dark purple fondant. Is it best to start with a dark color fondant (i.e. red for the maroon and blue for the purple) or just start with white and keep adding color?

Thanks for your help!

Of course it will be best to start with a dark color fondant. My fondant tends to turn really soft when I add too much coloring.

For a deep, rich maroon I do start with a Red and add a LITTLE, TINY bit of black at a time. Yes for purple you could start with a blue and add red, but why not make one big batch of red half for your maroon and use half for your purple? That's what I would do.