Colored bubbles arise after 15-year quest

Zubbles

Standard food coloring or dyes have no effect; they simply run down the sides of the bubble, creating a drop of color on the bottom. Other dyes can stain bubbles, but when they pop they also stain clothes, dogs and eyes, as Kehoe discovered during one accident. Other tests, including one for a bubble dye that washed out, didn’t fare much better.

I don’t know about the food coloring running down the side — the dilution is so great that for amount I’ve added when I tried this, the effect is simply unnoticeable.