In the photograph, P.S. Krøyer is sitting with his large canvas near the water’s edge, painting one of the models for the painting Boys Bathing from 1892 (location unknown). At the beginning of the 19th century, several French artists would complete their works in the open. To a certain extent, artists have always been working in the open, but before the 19th century it had been common practice for artists to complete their works in their studios. During the 19th century plein air painting became an artistic practice in its own right, and in the 1870s, the French impressionists became known for their quick and spontaneous sketches of nature.

When the Skagen painters started coming to Skagen in the 1870s, it had become fashion to complete one's paintings in front of the subject - including large canvasses. It was called plein air painting (from the French en plein air, meaning in the open air), because the artists were sitting out in the open whilst painting. This way they were able to capture the light and the colours directly onto the canvas. It was because of plein air painting, the unique landscape, the special environment, the colourful local population – and the fact that other artists were staying in Skagen – that an artists' colony emerged in Skagen in the late 1870s.