Posted by Jeffrey (Scottsdale, United States) on 21 June 2017 in Cityscape & Urban and Portfolio.

Location: Scottsdale, AZ

A couple of people have asked me why the sky in the photo I posted yesterday (and presumably, this photo is well) is such an unusual color. The answer is easy: The primary light source for this scene is a streetlight across the street and the color of light the streetlight's bulb emits is very yellowish.

When I neutralize a color cast during post-exposure processing of a photo, I do so globally, across the entire photo. In turn, this causes the colors of objects that were not lighted by the streetlight, such as the sky, which was therefore presented correctly, to now shift color. And when there are multiple light sources appearing in a single scene, as was the case here (because the sky is lighted by moonlight, not a streetlight), it can be impossible to correct the color globally with a single mouse click, because a separate correction is required for each light source, as well as for each instance where multiple light sources mix (such as the grass and concrete driveway, which are lighted by both the streetlight and moonlight.)

To correct the color balance in those situations requires making lots of individual selections and then correcting the color for every one one of them separately. And that can often be very difficult, if not impossible to do well, plus it requires a massive amount of work.

In the end, as a practical matter, the best one can hope to achieve is to pick a compromise color around which to neutralize the rest of the photo and accept that some colors, such as the sky, will look funky and/or unnatural. This also explains why the color of the sky is vivid blue in one photo, purplish in another photo, and a dusky mauve in a third photo, which is because not all streetlight bulbs emit the same color spectrum of light.

Of course, there is an alternative -- one that I usually favor, in fact -- and that is to convert color photos to B&W and sidestep this issue entirely. 8^)

A larger, higher-resolution version of this photo can be seen here: http://www.canyonero.com/files/1497752303.jpg