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.
 
Blue #1 and a tish of Red #27 to make a beautiful blue ake dye.  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.