I need to make some cartoon characters out of royal icing for my son's birthday cake. I want the colors to be as close to the real things as possible. Is there a technique to color-matching before you add it to the icing, or is it just trial and error until I get it right?
You can purchase icing gel color sets from Wilton for certain characters. Otherwise, I'd say its experience mixed with a little trial and error Familiarity with how the color wheel works also helps a lot!
If I'm trying to color match my buttercream to a certain color I experiment first. I use a styrofoam plate with a tablespoon of buttercream. I put my coloring around the plate. Then I start mixing keeping track of the amount and type of coloring I'm adding. Then let it set for an hour or so to allow the colors to darken and develop. (Very important to write down your "recipe" that you used to achieve the coloring). If I'm way off base, I only have a tbsp of icing to pitch. I also keep track of the brand of coloring using when I mix. I have a notebook that I keep track of my coloring formulas. HTH