Surge marks are streaks or lines that appear on a photographic image, caused by the sprocket holes of 35mm film. They occur when the film is agitated too vigorously during development, which can result in uneven chemical flow across the emulsion. These marks are usually unwanted and can affect the overall quality and consistency of the image.
Understanding surge marks is important for film photographers aiming for clean, professional results. By controlling agitation and handling the film carefully during development, photographers can minimise the appearance of these streaks. Surge marks also serve as a reminder of how the mechanical and chemical aspects of film photography interact to create the final image.