regresins

Regresins are a class of synthetic polymers primarily used in the production of photographic films and papers, particularly in black-and-white photography. These materials were developed to replace traditional gelatin-based emulsions in certain applications, offering improved stability and performance under specific conditions. The term "regresin" originates from the combination of "regression" (referring to the material's properties) and "resin," highlighting their resinous nature.

Regresins are typically composed of synthetic polymers such as polyvinyl alcohol (PVA) or other water-soluble resins blended with gelatin. This combination enhances the mechanical strength and dimensional stability of photographic materials, reducing issues like shrinkage or warping that can occur with pure gelatin-based products. They are particularly valued in high-end photographic papers and films where longevity and resistance to environmental factors are critical.

The use of regresins became prominent in the mid-20th century as advancements in polymer chemistry allowed for more durable and consistent photographic media. These materials are also employed in archival applications, where preservation of photographic negatives and prints over extended periods is essential. While regresins are less common in modern color photography, they remain relevant in traditional black-and-white processes, especially in professional and fine-art contexts.

The advantages of regresins include improved resistance to humidity, temperature fluctuations, and physical stress, which contributes to their longevity. However, they may require specialized processing techniques compared to conventional gelatin-based emulsions. Overall, regresins represent an important innovation in photographic materials, bridging the gap between traditional and modern photographic technologies.