Colors: Ultra Blue, Teal, White
Santorini is a very mellow blue gradient, check out Iceland if you want more pop!
Load a 1″ flat brush (or smaller width brush to pick up fewer colors) back and forth over the cake, using a small amount of water to moisten your paint.
You can either spray the cake or use a wet brush to moisten the paint.
Re-load making sure brush is lined up again with the correct colors. Hold the cake vertically so that any dripping paint will run down the color of the stripe, and not across the whole rainbow. When making strokes try not to twist the brush so that the colors overlap. To make your rainbow cakes last longer, put equal pressure on the brush so that you pick up an even amount of paint on the edges as in the center.
Rinse and repeat if colors start to get muddy. Note that fewer colors in your cake will often lead to cleaner strokes.
You can also use these cakes with face painting sponges to do base work or with and dauber sponges to make rainbow spheres that can morph into all sorts of cool things!