Making this long exposure (1.6 seconds) of Lake Louise in Alberta, Canada after sunset inspired me to read about the blue hour.
A scientist named Chappuis discovered that the ozone layer absorbs ultra violet light, and after sunset this Chappuis absorption has a significant effect on the color of the sky. I’m going to have to learn more about light wavelengths to understand this in depth.
As a photographer, I will remember the soft and soothing effect of this blue hour. Some artists enjoy photographing city scapes featuring yellow incandescent light during the blue hour. Have you tried it?