Indigo is such a particular color. I usually have trouble distinguishing shades between blue and purple. Ask me what color a GameCube is for example, and you'll probably get a different answer every time. It took some scouring, but I found this picture that I haven't really shared with many people, of the silhouette of a tender moment at a concert. I had a couple other options, but @jessamynorchard's post for this very same challenge today drew me to this image for the way indigo permeates so subtly yet clearly:
Like always, this was shot on my iPhone 6, and completely unedited.