Photographic chemicals could be flammable or even deadly, and results took a huge amount of work. The daguerreotype process of using mercury to develop pictures on polished metal, and the wet ...

Using the daguerreotype process—invented in France in 1839 ... in his train cars to conceal fugitive slaves. In the 19th century, photographic portraits largely replaced painted miniatures.

He was arguably the most artistic American landscape photographer in the 19th century ... camera and developing process technician. One reviewer admired Watkins' photographs for their "clearness ...