David Boston Photography

Reine with Olstinden (elev 2214 ft) in the background at blue hour
Canon EOS 5D Mark IV, EF24-105mm f/4L IS II USM, 50 mm, ISO 100, 25.0 sec at f / 8.0, © 2020, David W. Boston

As noted above, this photo was shot during the morning blue hour. Blue hour is the period of twilight (in the morning or evening) when the Sun is at a significant depth below the horizon and residual, indirect sunlight takes on a predominantly blue shade. According to Wikipedia, “Many photographers cherish blue hour for the tranquil mood it sets”. When photographing blue hour, it is recommended to include subjects that have artificial light sources, as in this photo, such as buildings, monuments, cityscapes, or bridges.