Stress marks are visible black lines or streaks on photographic film or paper, caused by friction, pressure, or mechanical stress during handling, processing, or storage. These marks occur when the emulsion-the light-sensitive layer on film or photographic paper-is physically disturbed, resulting in permanent lines that can affect image quality.
Stress marks are more common with delicate or improperly handled materials, particularly in large-format negatives or films with thicker emulsions. They can appear during winding, rewinding, or even when stacking prints too tightly. Preventing stress marks requires careful handling, using smooth rollers, avoiding excessive pressure, and storing materials under proper conditions. While minor marks can sometimes be retouched digitally or manually on prints, understanding and preventing them is essential for maintaining the integrity and quality of photographic work.