Painting or photograph? At first, it may be difficult to tell. Edward Steichen and other skilled photographers like Alfred Stieglitz and F. Holland Day formed the Photo Secession movement. Its members argued that an image could be manipulated by an artist-photographer to achieve a subjective vision, just like the painter and his paintbrush, thus elevating the photograph as fine art. Pictorialist creations like The Flatiron liberate the finished print from the camera’s mechanical, scientific roots—the end result seems to blur the line between the two mediums. The hazy street scene, with blurred figures, tall buildings, and overall atmospheric quality recalls the familiar Paris boulevard and other Impressionist imagery. The added pigmentation further liberates the photograph. The silhouetted trees and layered flatness should bring to mind Japanese woodblock prints, which were still in vogue by 1909.
(http://covenantarthistory.blogspot.nl/2015/04/impressionism-and-early-photography_24.html)
Edward Steichen's 1903 photo of the Flatiron Building is one of the earliest experimental uses of color film.
Stieglitz and Steichen weren't the first or the last to find the Flatiron Building a fascinating subject for their talents. As an icon of New York City, the landmark is a popular spot for tourist photographs, making it possibly one of the most photographed buildings in the world. But it is also a functioning office building which is currently the headquarters of several publishing companies.
The Flatiron's interior is known for having strangely-shaped offices with walls that cut through at an angle on their way to the skyscraper's famous point. These "point" offices are the most coveted and feature amazing northern views that look directly upon another famous Manhattan landmark, the Empire State Building.
..The Fuller Building, which soon came by the nickname of the "Flatiron Building," was Daniel Burnham's first building in New York City, and his most famous. It rises from a triangular lot formed by Fifth Avenue and Broadway.
Burnham designed the Flatiron Building as a vertical Renaissance palazzo with Beaux-Arts styling. It's hard to imagine a building more out-of-step with the dawning of 20th-century New York architecture.
...Burnham and Company forgot to include women's restrooms on each floor. The solution involved alternating the restroom gender designations by floor. That way, everyone was inconvenienced equally.
..Once construction began, work proceeded at an amazing pace. The steel was so meticulously pre-cut that the frame went up at the rate of one floor each week. By February 1902 the frame was complete, and by mid-May the building was half-covered by terra-cotta tiling. Final completion came in June 1902, after just one year of construction.
(http://art-now-and-then.blogspot.nl/2017/06/daniel-burnham.html)