Photography is not only about science. Every photograph is the result of a number of creative decisions by the photographer. To master the medium, photographers must have a profound understanding of the effects of light. Light can be used to show detail, create shadow, describe colour, and contribute to the mood of the photograph.
The American Alfred Stieglitz is best known for encouraging the widespread acceptance of photography as an art form. He did so through "Photo-Secession," a group he founded in 1902, its quarterly publication, Camera Work, and his art gallery in New York. He supported the first American exhibitions of great European modern artists, such as Matisse and Picasso. Their paintings were exhibited alongside photographs by contemporary photographers.