Identification

Silver Gelatin Developed-Out Prints (DOPs)

common use: 1890-2000

Image Tone

Although varying greatly, image tone can be used to identify DOPs when used in combination with other observations. DOPs have been toned in a variety of colors over the process's long history; however, certain tones are more prevailant than others. DOPs that have not been toned are neutral black in color, unless severly deteriorated. The most common toners are Sepia, Polysulfide, and Selenium, which produce varying shades of brown. These toners were particularly popular in the 1920s and 1930s .

Deterioration

Early DOPs, in particular, had poor stability and can often be identified by their deterioration. Yellowing and a loss of highlight detail can all be indicators of DOPs, particularly those from the late 19th and early 20th centuries.

Silver Mirroring

Silver mirroring is a type of deterioration in which silver originating from the image migrates to the surface of the print, forming a metallic sheen. The effect occurs most often in areas of higher density, such as shadows. Although this form of deterioration can happen in several other processes, it is most common in DOPs.

Layer Structure

The majority of DOPs have either a baryta layer or a pigmented polyethylene layer between the emulsion and the paper support that acts to obscure paper fibers. Under relatively low magnification one can inspect the surface of a print for the absence of visible paper fibers. DOPs have been made with thin or even no baryta layers, however, so the presence of paper fibers does not completely disqualify the print as a DOP.

Prevalence

The DOP process has been the dominant black-and-white print process over the last hundred years. This fact alone can often be the easiest way to identify the process. A familiarization with the style and design aspects of the 20th century can be a relatively fast and accurate tool. Things to pay particular attention to are subjects’ appearance and enclosures, deckeled edges, and backprints, if present.

Resin Coating

In the late 1960s Kodak introduced the first resin-coated photographic papers. These papers have a support coated on the back with polyethylene and on the front, directly below the emulsion, with pigmented polyethylene. Unmounted resin-coated prints are easily identified by their smooth plastic back side. Resin-coated DOPs can also exhibit a unique form of deterioration known as redox blemishing. This is caused by the formation of colloidal silver and appears as orange markings on the print.