Lake dyes give the best color performance in bath bomb type products. They create beautifully colored water and do not leave a mess in the tub.  What you see is what you get in the bath bomb mix.  I also use the lakes in my bubble bath, sugar scrub, lip balms and bubble scoops.  Briliant colors in all products using very little.
 
Yellow #5 lake dye and Blue #1 lake dye blended together for the perfect Kelly green.  These are high dye lakes that arrive batch certified from the factory.  After they arrive in big drums, we rebag the lakes into 1 oz sizes.  I am not a certified rebagger.