This is an example of a Daguerreotype image. The process was invented by Louis Daguerre. This process is done by exposing a light sensitive metal sheet, creating a direct positive. He then would immerse it in salt. The downside of this process was that it was very expensive.
The second photo is an example of a Calotype image. This process was invented by William Fox Talbot. In this process the subject was exposed to light sensitive paper producing a paper negative. A positive about this process was that it was faster and less expensive, but since the images were printed on paper the quality of the image was not as good.
In the third photo is an example of the Wet Collodion Process. This process was invented by Archer. This process was done by coating glass plates in collodion, after they were coated they would be immediately exposed and developed while they were still wet. A positive about this process was that it was much faster than previously done and cost less money. The main downside to using this process was that only people who were skilled to use photography could use it, it was to complicated for the general public.