What is the appearance of a straight white border on a film?

A straight white border on a film indicates an undeveloped area due to insufficient developer chemicals. When X-ray film is processed, it goes through various stages, including development, where it becomes visible. If the developer concentration is too low, it fails to properly develop the areas it comes into contact with, leading to a clear or white appearance where the film did not receive adequate processing. This phenomenon can occur if the developer solution is diluted incorrectly or has been exhausted and is no longer capable of properly developing the film.

In contrast, an unfixed area from low fixer chemical would typically appear as a milky or cloudy area, as the fixer works to clear unexposed silver halide crystals. Chemical contamination could manifest in various ways, such as streaking or discoloration, and broken film emulsion could lead to either a scratch or a more sporadic appearance rather than a straight white border. Therefore, recognizing the characteristics of film development is crucial for understanding and identifying processing errors represented in the images.