Endless Stair, photo by Harold Davis. View this image larger.

On Friday Julian had a half day of school. I picked him up early, and we went into San Francisco where I took the photo of a spiral stairway at 2 Embarcadero that is the basis for this post-processed digital image of an endless stairway. The post-processing was similar what I used for the endless doorways in World without End.

The stairway at the Embarcadero Center was narrow and in a dimly lit spot, somewhat exposed to the elements. I used a wide angle to make the small space seem expansive. My camera was on tripod, with a long exposure for maximum depth of field. I wanted everything to be in focus so that there was a good sense of depth.

The lighting was very mixed, with a wide variation of color temperatures, predominantly flourescent blue at about 3500 Kelvin and ambient reflected daylight at about 5600 K, but also some incandescent from a nearby fancy watering hole. I’m not sure what the patrons of this restaurant made of Julian and me diligently photographing this dingy stairway, but some of them were certainly observing the spectacle through a plate glass window. And thanks for the rather elegant mensroom, we made good use of it when the photos were “in the card”.

My first step in post-processing was to open different exposures from the RAW, balancing each to a different color temperature light source, and exagerating the cast of the light.

After I combined the RAW conversions, I used a process that is essentially iterative, or maybe even recursive: I made successively smaller copies of the original image, and then pasted it on a layer of the original. Each new copy was smaller than the original roughly in the same proportion.

Once the layers were complete, I archived a copy, flattened the image, and then did minor retouching.