Cleaning the “silver mirror” with a triethanolamine-based strategy for black-and-white silver salt negatives

It is well-known that black-and-white silver salt negative films are prone to “silver mirror” phenomenon, which diminishes image quality and imparts a metallic sheen to surface. This study developed an efficient cleaning system based on isomeric alcohol ethoxylates eight (TO-8)/ Triethanolamine (TEA) (4:96, v/v) to address the “silver mirror” phenomenon. Through systematic performance optimization, the cleaning agent effectively removed Ag2S particles after 180 min of immersion, significantly improving the optical properties and surface morphology of films without compromising their mechanical strength. XPS and ATR-FTIR analyses confirmed the complete removal of Ag2S and revealed an increase in β-sheet content within the gelatin structure, which reduced the binding affinity to Ag2S and facilitated particle release. Grayscale analysis demonstrated notable recovery of image details and overall enhancement in image quality. The proposed method offers a safe, reliable, and operator-friendly cleaning strategy for the preservation of silver gelatine photographic objects.