Abrasion Marks or Streaks
Appearance
Fine, black lines usually resembling pencil scratches run in the same direction.
Cause
Marks or streaks are formed by friction on the film emulsion caused by improper handling or storage at some time between its manufacture and development. These streaks may be readily produced by laying two films emulsion-to-emulsion and sliding one across the other when particles of dust are present between the sensitized surfaces.
Remedy
Take great care in storing film and other sensitized material. Store boxes containing such supplies on end so that no pressure is exerted on the surface of the emulsion. Take care not to rub or drag a piece of sensitized material over a rough surface, either before or during development.