Thank you for your comments. I'm glad that you like the pictures. They are a bit misleading because the place was really
dark, about EV 9. I literally couldn't see what I was stepping on, or my hand in front of my face. Exposures on the first three images were up to 13 seconds, centered on 3 seconds at f11, ISO 200.
For anyone who's interested, the fourth image is a story in itself. It was never intended to be a 'real' image at all, nor HDR. My shooting buddy, Kathleen, was walking up the stairs and stopped in front of the window when I asked her something. I thought it looked cool enough to make a portrait for her, so I banged out a bracketed set, all of which I badly underexposed because of that bright window. Damn, next time, I'll actually think first. I never even opened the images in Photoshop, they were that dark.
So, one boring night (over three years later), I got the idea to run them through Photomatix just to see what was there. Interestingly, there was enough detail in the formerly black interior to take a shot at tone mapping. Then I got the ghost idea. I wish I'd taken a shot without her in the picture, since that would have made creating the ghost relatively easy, but I didn't. Also, Kathleen hadn't stood still for all five shots, so there was some movement that I had to deal with. To make things worse, her camera, tripod and camera bag were clearly visible, and she had a surgical mask on (!); so I had to clone them out. But how to make her transparent? That was accomplished by cloning lots of small details over her at limited opacity, essentially building the scene behind her one piece at a time. The rest, I simply painted in with the brush tool. It took a day or so to get it right. Finally, I painted in the light bulb because I thought I needed an eye-catching detail on the left side. I'm still not sure that it was worth all that effort, but some people seem to like it.
Here's the lightest of the original RAW captures, as shot, and again, the final image:
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