Wet plate collodion

The collodion process was a photographic method introduced in 1851 by Frederick Scott Archer. It was developed to overcome the limitations of both the daguerreotype and the calotype and quickly became the dominant photographic process of the mid-19th century.

The process is based on a glass negative, combining the fine detail of the daguerreotype with the reproducibility of the negative–positive system introduced by the calotype. A glass plate was coated with collodion containing light-sensitive silver salts, exposed while still wet, and then developed and fixed before drying. This requirement defined the wet collodion process and made portable darkrooms necessary for outdoor photography.

Collodion negatives produced images of high resolution. The smooth glass support eliminated the visible texture associated with paper negatives, resulting in sharp and detailed images. The process was faster and less costly than the daguerreotype and allowed multiple prints to be made from a single negative.

The collodion process is closely associated with albumen printing. Albumen prints offered high contrast, fine detail, and a glossy surface, making them well suited to the sharpness of collodion glass negatives. Together, collodion negatives and albumen prints formed the standard photographic workflow from the 1850s to the 1870s.

In stereo photography, this combination was particularly important. Collodion glass negatives provided excellent image clarity, enhancing stereoscopic depth, while albumen printing enabled large-scale commercial production of stereoviews. As a result, the majority of 19th-century stereoviews were produced using collodion negatives printed on albumen paper or glass.

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