The wet plate collodion process and ambrotypes

The wet plate collodion process was invented by Frederick Scott Archer in 1851.  The new process was instrumental in the progression of photography which allowed sharp glass negatives to be used for making prints.  For over 20 years the process dominated the photographic world until the introduction of the dry plate in 1871.  It should be noted that Archer gifted the process to the world and died a few years after his discovery, penniless. 

The process for creating ambrotypes or glass negatives is similar to that of ferrotypes, also known as tintypes.  Where they differ is their use of material.  With tintypes the collodion is poured over a black japanned tin plate creating an instant positive image.  For an ambrotype or negative, the collodion is poured directly onto clear glass.  The finished product has two functions.  One, being a glass negative so that several prints can be made from a single plate (Albumen prints were very popular in that era).   And the other is the positive ambrotype.   Once the plate is shot and developed (on site), the glass plate is dried and the surface varnished for protection. At this point it is backed with black velvet.  This simple procedure transforms the negative image into a positive image.  Like tintypes, black japanning can also be used on glass adding a warm black in the shadows.  Additionally, the back of the glass plate can be painted with black acrylic paint with similar results.  

There is a sense of depth in ambrotypes that other photographic processes can’t replicate due to the separation of the image surface and the backing.  The thickness of the glass creates the space needed between the image and backing, creating a slight, but beautiful effect.

  Negative (Left) and Positive (Right) Ambrotype

Daniel Afzal, www.pictoriallight.art