Drying marks are irregular streaks, spots, or patterns that appear on a photographic film's emulsion when it dries unevenly after processing. They are often caused by surface tension or water droplets that do not drain uniformly.
These marks can be minimised or prevented by using a wetting agent in the final rinse, which reduces surface tension and allows water to drain evenly, producing smooth, clean negatives. Controlling drying marks is important for maintaining image quality, especially when scanning or printing film, as imperfections can affect sharpness and tonal consistency.