The so-called Red Shirt School of Photography, which referred to the practice of using red elements, such as shirts, caps, and sweaters, to brighten photographs in National Geographic magazine (above, hikers wear matching red-tasseled caps in 1957 in Trollstegen, Norway), emerged during the 1950s.

At that time, a faster speed of Kodachrome film allowed photographers to move further beyond the rigid and posed photos required by slower color film processes.

Melville Grosvenor, editor of the magazine in the 1950s, said the red-shirt strategy helped enliven expedition photographs, which otherwise featured khaki-clad subjects: "There was no pep to it. But when a fellow had a red cap on—just a red cap—it would add a little color to the picture."