During the early part of the 1800’s, Jacques-Mande Daguerre developed the Daguerreotype. This relied on being put into a camera obscura and then developed in Mercury vapours on a metal plate, this process was only able to capture one image per plate and, this wasn’t very duplicatable which isn’t like today where an image can be duplicated many times over, and have copies everywhere.
The Daguerreotype was highly successful, not in Europe where it was developed, but in America in 1850’s New York. The most successful photographers had studios on the top floor of buildings, just off of Broadway (because of the amount of light that you are able to get, located at the top of buildings, and almost always on the north side because that is where you would get the most amount of natural light.).
This practice was the most common among early photographers and created a one off print which had to be kept under a bit of glass as the slightest knock could ruin the print and was really hard to repair and if it was repaired it had to be done by a professional, which I imagine would be quite expensive.
“The vast majority of American photographs made before the Civil War era are portraits.”(The Daguerreian Era and Early American Photography on Paper, 1839–1860 | Essay | Heilbrunn Timeline of Art History | The Metropolitan Museum of Art, 2016)
The first photographic portrait of a human being was of Robert Cornelius in 1839. he inscribed it with “The first light Picture ever taken. 1839.”