What is the sign of exhausted fixing solution?

The presence of a milky coating on the film is indicative of an exhausted fixing solution. The fixing solution plays a crucial role in the development process of radiographic films by removing unexposed silver halide crystals from the emulsion. When the fixing solution becomes exhausted, it is less effective at performing this function, allowing remaining unexposed crystals to remain on the film. This leads to the film exhibiting a milky appearance, as the unprocessed areas do not have the clarity expected in properly developed film.

Understanding this is important for maintaining quality in radiographic images. A milky coating makes it challenging to interpret the radiographs, therefore highlighting the importance of regularly monitoring and replacing the fixing solution to ensure optimal film quality.