The making of a night photograph

During twilight, while the sky is getting darker, the balance between the light of the illuminated buildings and the light of the sky is constantly changing. It is difficult to find the best moment for a balanced photograph. The artificial lights should stand out clearly, but the sky should still be blue. To find the optimal exposure can also be difficult. Therefore, I usually take a sequence of photographs at different times and with different exposure bias settings.

There was a special problem when making this photo. When I was ready to take a sequence of photographs, all lights were switched on except the ones on the surface of the large building (Klimahaus). So I had to be prepared to combine two images, i.e. take the lights from a later photo and place them on a photo taken earlier. This can only be done if the two images are congruent with respect to each other. Therefore, I switched off Auto Focus after having taken the first shot. Otherwise, the camera would autofocus prior to each shot which would lead to varying focus settings. The images of the sequence would thus have nonidentical reproduction scales, i.e. the images would not be congruent. If the image with the lights is not congruent with respect to the basic image, the lights would be misplaced.

Exposure was critical. Due to the ultra wide-angle lenses large 104° horizontal angle of view, the color of the sky spans from light blue on the left-hand side of the scene (where the sun went down) to deep dark blue on the right-hand side. Images 1 to 3 are overexposed with respect to the blue component of the sky on the left-hand side, resulting in banding, i.e. a non-smooth color gradient. Image 4 is exposed correctly. On the subsequent images, the sky is too dark. On image 7, the lights on the surface of the large building are switched on.

From the sequence of shots, I chose image 4 as the basic image. The lights of the building were cut out of image 7 with Gimp’s Select by Color tool and pasted onto the basic image. From images 3, 5 and 7, illuminated windows of the hotel in the background were added. The elevator door with the brightly lit cabin behind was replaced with the elevator door from image 7. To intensify the reflections on the water surface, image 7, set to 25% opacity, was added in Lighten only blending mode.

The making of a night photograph

Protocol of a shooting session (Night photographs, series 2, image 15)