Surf, Kirby Cove, photo by Harold Davis. View this image larger.

On a recent overcast evening, with my guest from Finland, on a bluff above Kirby Cove, I waited for the night lights of the Golden Gate Bridge.

To pass the time, I tried long exposures of the white surf on the dark beach. My idea was to get the exposure as long as possible, so I used a circular polarizer to make things darker (and increase the tonal contrast). I also wanted to underexpose the overall image, because I knew I could pick up the white waves in post-processing.

This was an image that I pre-visualized in black and white, although I exposed in full digital RGB color and converted using the techniques I explain in The Photoshop Darkroom.