Answer:
An indicator has to be able to change colors as the pH of the solution approaches ithe indicators pH range.
For example, universal indicator starts out as a yellowish color in an acidic solution, then as it grows more neutral(more towords 7) it becomes a greener color, and as it grows more basic, it starts to become a blue color.
Universal indicator will give you an indication of HOW acidic or alkaline a solution is, depending on the exact color. Litmus can only turn red or blue and can't distinguish between differing amounts of acid or base