
San Luis Valley, CO.
If you have ever photographed at sunset or sunrise with a bunch of photographers, chances are you have heard someone talk about civil twilight. Civil twilight is defined as that period when the sun has set, but there is still enough light to see terrestrial objects. In other words, about 30 minutes before sunrise, and about 30 minutes after sunset.
Many photographers pack up when the sun sets, but you might want to wait just a little longer. Civil twilight can produce a beautiful range of pastels colors and transform the landscape. The image at the top of this post was taken at sunset. Nice warm light and a beautiful snowy peak.

San Luis Valley, CO.
This image is during the last rays of sun. Classic pink light dappling the peak, and what most landscape photographers anticipate all day long.

San Luis Valley, CO.
But then civil twilight begins. The sun has set, but the sky begins to turn shades of pink and purples as the sun slowly sinks further behind the horizon. It is hard to believe the sky was pink like this, but the color band lined up perfectly behind the snowy mountain.

San Luis Valley, CO.
The light show was over. 20 minutes after sunset the sky turned purple behind the peak. Light was waning quickly, and using a tripod was critical to photograph using slow shutter speeds. Finally the purple turns to gray as civil twilight ends. Look at the four images above. The light and landscape transformed over the course of about 40 minutes.
Civil twilight is something every outdoor photographer should consider. Some areas, like White Sands NP, photograph the best during this time. The white sand reflects the pastel colors during civil twilight, creating unbelievable scenes in the sand dunes. Keep on shooting after the sun sets, you might be surprised at how the scene transforms.