Fotograafiaplaate

Fotograafiaplaate, also known as photographic plates, were an early form of photographic medium. They consisted of a glass plate coated with a light-sensitive emulsion, typically containing silver halide crystals suspended in gelatin. These plates were used to capture images before the advent of flexible film.

The process of using photographic plates involved preparing the plate by coating it with the emulsion, exposing it in a camera, and then developing and fixing the image. Developing involved chemical treatments that converted the exposed silver halide crystals into a visible silver image. Fixing removed any unexposed silver halide, making the image permanent.

Different types of emulsions were used, varying in their sensitivity to light and color. Panchromatic emulsions, for example, were sensitive to all colors of the visible spectrum, allowing for more accurate color rendition in black and white photography.

Photographic plates were fragile and relatively heavy compared to later film formats. However, they offered superior image quality and detail, which was particularly important for scientific and astronomical photography where precise measurements and fine details were crucial. The use of photographic plates gradually declined with the development of more convenient and affordable roll film in the late 19th and early 20th centuries. Despite their obsolescence, many historical photographic plates still exist, serving as valuable historical and scientific records.