How does cabbage juice indicate the relative strength of acids and bases?

Cabbage juice has a dye in it ghat changes color according to acid or base. Let cabbage juice dye be called J. Then at low pH, cabbage juice dye has the form HJ. If OH- be added and the pH goes up, then HJ + OH- ===%26gt; J- + H2O. HJ and J- are of different colors. So they can indicate whether solutions are acidic or basic.
Loosing eyelid crease.