Eric Cahan’s beautiful “Sky Series” project captures sunrises and sunsets from a variety of geographic locations. Cahan takes pains to include the exact GPS coordinates where each of them were taken, and even links to that location on Google Maps. The colors are remarkably rich, which might lead some to assume that they’ve been extensively retouched through digital means. Cahan explains:

In fact, very little Photoshop is used. I will only tone photos to match the paper type and, in some cases, add a bit of color curves. The actual process is done with colored resin filters I make myself and hold in front of the lens before I shoot a picture. When a color filter is used against a blue sky, it always alters the color of the sky. I know the colors I am trying to conjure and choose the filter accordingly.

One thing I noticed is that the dramatic color ramps of each image really reveal the limitations of JPEGs and computer monitors; I’m seeing much more color banding than I imagine the artist would like.

See more at ericcahan.com.