These images have been created using the mid-1850s wet plate collodion process – often also referred to as a Tintype when made on metal, or an Ambrotype when made on glass.
A wet plate image is created by hand-coating a plate with liquid collodion and submerging it in silver nitrate to create a light sensitive plate. The plate is loaded into a 8×10 large format field camera, and the exposure is made.
The image must be immediately developed while the plate is still wet – hence the name ‘wet plate’. Each shot takes around 15 minutes to create and produces a one off, unique image.