In chapter 16 The Awakening how does Chopin use natural imagery to help the reader understand Edna's mood's?

In Chapter 16, Chopin uses the imagery of lightness and darkness to illustrate the change in Edna's world after Robert's departure.

"Robert’s going had some way taken the brightness, the color, the meaning out of everything. The conditions of her life were in no way changed, but her whole existence was dulled, like a faded garment which seems to be no longer worth wearing."