增色 is a verb-object compound (离合词) meaning 'to add luster, color, or beauty to something', often used figuratively to describe enhancing the appeal or quality of an event, place, or work. As a separable verb, you can insert aspect markers or measure words between the syllables, e.g., 增了色 ('added luster') or 增一次色 ('add luster once'). The object being enhanced is typically introduced with 为 or 给 before the verb.