Lunar New Year

The color red is used everywhere in Chinese New Year decorations. Did you know that the red pigment, also known as vermilion, originated from the toxic ore of mercury? This pigment appears red because it absorbs all light with higher energy than red light.

The highest-energy visible light is violet, the lowest-energy visible light is red, and the other colors of the rainbow are intermediate in that order. Which of these colors could be created by using a threshold which absorbs all visible light with higher energy than that color?