The camera obscura was conceived in prehistory and developed in the Common Era, with the earliest written account dating back to 400 BCE. The term "camera obscura" was first used in 1604 by German astronomer Johannes Kepler. 

Sometimes called "camera-less photography" as the as the image was created by placed objects on light sensitive material and exposing it to light, creating a silhouette.  Variations of the technique were used in scientific fields, such as the medical X-ray.

1839 - The daguerreotype is a direct-positive process, creating a highly detailed single image on a sheet of copper plated with a thin coat of silver without the use of a negative. The process required great care. The silver-plated copper plate had first to be cleaned and polished until the surface looked like a mirror.

1841 - developed by William Henry Fox Talbot of Great Britain.  In this technique, a sheet of paper coated with silver chloride was exposed to light in a camera obscura, with those areas hit by light becoming dark, thus creating a negative.  Talbot is also responsible for discovering gallic acid used to develop the image and accelerate the process with shorter exposure times from one hour to one minute.

1851 - The collodion process, mostly synonymous with the "collodion wet plate process", requires the photographic material to be coated, sensitized, exposed, and developed within the span of about fifteen minutes, necessitating a portable darkroom for use in the field.  The collodion process thus combined desirable qualities of the calotype process (enabling the photographer to make a theoretically unlimited number of prints from a single negative) and the daguerreotype (creating a sharpness and clarity that could not be achieved with paper negatives). Collodion printing was typically done on albumen paper.

1867 - The extreme inconvenience of exposing wet collodion in the field led to many attempts to develop a dry collodion process, which could be exposed and developed sometime after coating. Dry plates are pieces of glass plate that are coated with a gelatin emulsion that when exposed to light will capture an image. It was a revolutionary photographic process in the late 19th century, and gave photographers the opportunity to take photographs anywhere they wanted. 

1888 - George Eastman developed a machine to coat glass plates in 1879 and founded the Eastman Film and Dry Plate Company in 1881. Gelatin silver print paper was made as early as 1874 on a commercial basis, but it was poor quality because the dry-plate emulsion was coated onto the paper only as an afterthought. Coating machines for the production of continuous rolls of sensitized paper were in use by the mid-1880s, though widespread adoption of gelatin silver print materials did not occur until the 1890s. The earliest papers had no baryta layer, and it was not until the 1890s that baryta coating became a commercial operation, first in Germany, in 1894, and then taken up by Kodak by 1900.