Winter and Summer

"The structure of Winter and Summer is based on the tilting of the earth as it journeys between the seasons.
The camera faces south across a tidal estuary. Most of the picture surface is comprised of sky and water. From the foreground to the middle distance, numerous small boats swing to and fro on their moorings.
The film is in two parts of equal length, and each part consists of a time lapse record of one complete day. In the first part, a day in midwinter, one frame was taken every ten seconds from first light until nightfall. In the second part, a summer day having exactly twice as many hours between sunrise and sunset as the winter day, one frame was taken every twenty seconds.
When projected at 24 fps, the Winter day appears to be the same length as the summer day, since both sections of the film contain the same number of frames. However, in order to achieve this effect, the summer day is in fact being seen at double the speed of the Winter day.
Rather than being arbitrary, the filming speed is controlled by the same natural phenomena seen within the frame, where the changing seasons effect the light, colour of foliage, and the absence/presence of people."
(Chris Welsby)