Reading 7

Ritzenthaler, M. L.; G. J. Munoff; & M. S. Long. (1984). "2. History of Photographic Processes." Archives & Manuscripts: Administration of Photographic Collections. Chicago, IL: Society of American Archivists. (pp. 27-54).
ISBN: 0-931828-61-9

While the chapter "The History of Photographic Printing in the 19th Century" from Care and Identification of 19th-Century Photographic Prints was helpful, its limited scope meant that many photographic processes I might encounter in my work in archives were not covered. This chapter provided a broader overview of the history of photographic processes, and I found it better organized and easier to follow than the previous reading.

The authors begin by explaining that it is essential that archivists be familiar with photographic processes because this information can assist them in dating images and the means by which a photograph was produced influences the types of conservation and preservation treatments most appropriate for that image. After this introduction, the authors provide a brief description of "basic photographic principles" (29), defining negative and positive images and the basic components of photographs, the base, the emulsion, and the light-sensitive salts. They also include a description of the general process used to produce photographic images. This section includes definitions of printing-out papers and developing-out papers. Printing-out papers were most prevalent before 1890 and are placed in direct contact with the negative and exposed to light through the negative--sometimes for more than a day--to produce the image. Developing-out papers are exposed for a much shorter time and do not have to be placed in direct contact with the negative, allowing for prints that are larger than the negative. The exposure does not produce the image on a developing-out paper; rather, the paper must be chemically processed to produce the image. The authors also describe the fixing and toning process.

The majority of the chapter is devoted to sections describing the major photographic processes. Each section gives the history of the process and describes the process itself, including the specific chemicals used and the techniques used by photographers. The sections also often include advice on identifying those processes by examining extant examples. These sections are well-illustrated, and most processes have at least one image to serve as an example.

The earliest processes the authors discuss include daguerreotypes, plain salted prints, the calotype process, platinum prints or platinotypes, and cyanotypes. They also describe processes using collodion emulsions, which include ambrotypes, tintypes, collodion wet plate negatives, and collodion positive transparencies. They then describe processes using albumen emulsions, which include albumen prints and crystoleums.

The authors then devote several sections to discussion photograph formats, which, they emphasize, are not particular processes but rather ways in which all the various types of photographs discussed were presented. The formats they describe include cartes de visite, stereographs, and photo albums.

They then describe photographic processes using gelatin emulsions, which include gelatin dry plate negatives, Eastman paper and gelatin negatives, cellulose nitrate film, safety film, and gelatin silver prints. Another section is devoted to attempts to create "permanent" photographs and photomechanical processes which do not rely on light-sensitive material. The processes they describe include gum bichromate prints, carbon prints, photogravures, woodburytypes, and the collotype process.

They then move on to color processes. The screen plate color processes they describe include the joly plate and the autochrome. The authors then discuss the tri color carbro process, dye transfer prints, chromogenic development materials, modern color prints, and dye diffusion transfer processes (such as Polaroid images).

Overall, this is a very helpful, concise overview of photographic processes that provides useful background for any archivist working with photographs and it would serve as a convenient reference.