Camera Obscura
The camera obscura (meaning dark chamber in Latin) was a very early form of photography which was composed of a dark room with only one tiny hole that had a lens. This created images on the far wall inside the dark chamber which would be traced by the artist, this gave the artist a sketch that they would later turn into a painting.
Daguerreotype
The daguerreotype was one of the earliest forms of photography ever, it created images through a chemical reaction with iodine and mercury vapor on a silver plate fixed with a salt solution. The image was clear but there was only one copy of it and the process of retaining the image was quite dangerous due to the chemicals.
Talbotype/Calotype
Developed in 1835, this process produced a negative image on paper which was treated with silver. The paper with the negative image was placed on new paper which was exposed to light, this crated a positive and final image. Luckily with this method of photography, it was possible to create multiple copies of this image, but, the image transfer caused the image to not be as clear as earlier methods of photography.
Collodian Wet Plate Process
This form of photography allowed for a clear image that COULD be reproduced multiple times. The process started by brushing a glass plate evenly with collodian, then dipped in a silver nitrate solution. After this, the sheet was placed in a camera and after the photo was taken it immediately had to be produced and left to dry. This process was not easy and could mess up in several ways, but it worked well.