kalotypie

Kalotypie, known in English as calotype, was an early photographic process developed by William Henry Fox Talbot in the 1840s. It was one of the first negative–positive methods, allowing multiple prints from a single image. The process used paper coated with light-sensitive silver salts to produce a paper negative for contact printing.

Procedure: Paper was sensitized with a solution of silver nitrate and potassium iodide to form silver iodide. After drying, it was exposed in bright light to create a latent image. The image was developed with gallic acid and silver nitrate, then fixed with a hypo bath. Positive prints were made by contact printing the negative onto sensitized paper, commonly salted paper.

Historical significance: Calotype offered reproducible images unlike the single-image daguerreotype and influenced later photographic printing. It allowed photographers to experiment with composition and to reuse negatives. Talbot published The Pencil of Nature (1844–46), which documented calotype images.

Decline and legacy: The calotype declined after the mid-1850s with the advent of the wet collodion process, which yielded sharper images and faster exposure times. Nonetheless, calotypes, sometimes called Talbotypes, are important as precursors of modern film and printing techniques, and the term Kalotypie remains a historical name in German-language sources.