What is the best visual clue for a general reader observing an elliptical galaxy that indicates a population dominated by older stellar generations?

Answer

A fuzzy, featureless blob of pale yellow or orange light

The best visual clue is spotting a galaxy that looks like a fuzzy, featureless blob of pale yellow or orange light, strongly contrasting with the blueish spiral arms of neighbors.

What is the best visual clue for a general reader observing an elliptical galaxy that indicates a population dominated by older stellar generations?
galaxyastronomytypestarstellar death