The antonyms for the phrase "became colorless" are abundant, as there are numerous words that imply adding color or vibrancy. Some possible antonyms include "bloomed," "glowed," "brightened," "blushed," "sparkled," "shimmered," "vivid," "radiant," "enlivened," and "animated." These words imply a richness, liveliness, and vibrancy that is the exact opposite of the dull, lifeless quality of something that has become colorless. If you want to describe something as full of color and light, you should not use any of the words included in the antonyms for "became colorless", but instead turn to more descriptive, vibrant language.