What type of food coloring/dye should I use to create rich colors ?

The supermarket liquid coloring will never give you intense colors no matter how much you use. You will need to get the paste colors from a kitchen supply or cake decorating store. However, no matter what you do, the colors tend to taste bitter. Almond extract or something else strong might help cover up the taste.

Your best bet is to use gel colors. They are a lot thicker and make for deeper colors. Wilton makes them, I know. The food coloring you get in the grocery aisle is too thin and would take so much of it to get the color you want. If all else fails, go to your local bakery and see if they'll sell you some colored frosting, most bakeries will sell by the pound.

Check out the Wilton food colors. Walmart has them, Michael's and Jo-Ann's. The ones in grocery stores are typically too week for the more saturated colors. I do believe they come in gels and liquids.

mccormic has really nice colors, there food safe, so u dont have to worry about getitng sick they also have dyes that are allergy safe