Wow. Thank you all for your comments!
It's a composite of four shots, taken as far far back as a year ago in June. That was the original building that makes up the base of the shot. One sky photo was taken last year, The other two, Last month. Masks were made of the two windows. then I overlaid the skies according to distance from the lens and either cut out around or pasted in the mask. The two forward sky layers were given some transparency to show texture. If you look at the interior, you may be able to see the bench in the building and the ceiling joists. The two most time consuming parts were building the masks, 4-5 hours, of which I spent a little too much time (had to start over a couple times), and then selecting the skies. That was a little tricky finding formations that seemed to flow together- probably another 1-2 hours. I still need to go over the big sky layer and do something with it. A bit too drab. I didn't want to detract from the window opening, but could have went farther.
An additional note, the photos themselves represent 3, 2 hour sessions and one 16 hour day with a 150 mile round trip drive. Of course these sessions/trips produce multiple useable photos, so it's hard to calculate exactly how many hours went into the image.
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