Colour toning is a photographic process used to alter the colour of a black-and-white print by converting the black metallic silver into a coloured compound. This technique can add warmth, coolness, or artistic hues such as sepia, blue, or selenium tones, enhancing the mood and aesthetic of the image. Colour toning is widely used in fine art photography and darkroom printing to create unique visual effects, increase archival stability, and provide a distinctive, timeless look to black-and-white photographs.