from the group: Gelatin POP

Gelatin POPs

common use: 1885-1910


The majority of gelatin POPs were produced as cabinet cards, a 4.25” x 6.5” paperboard mount format. The process was used extensively for commercial portraiture in the 1890s.

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Image Tone and Deterioration

Undeteriorated gelatin POPs have characteristic reddish-brown to purplish-brown image tones, a product of gold toning. However, most gelatin POPs have undergone some degree of sulfiding, a process initiated by residual sodium thiosulfate (fixer) that causes the image tone to turn greenish to yellowish-brown, accompanied by fading.


(click to enlarge) (click to enlarge)
(click to enlarge) (click to enlarge) (click to enlarge) (click to enlarge)


Layer Structure

Gelatin POPs have a baryta 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.

30x Magnification
30x Magnification