What issue arises if a film is placed in the fixer before the developer?

When a film is placed in the fixer before the developer, the primary issue that arises is that no image will appear on the film. The fixer solution is designed to remove any unexposed silver halide crystals from the film after it has been developed. If the film has not gone through the development process first, the fixer will essentially wash away all the silver halide crystals, which means that there will be no latent image to develop and, consequently, no visible image will be produced.

This process is critical because developing the film first is necessary to convert the latent image into a visible one. The developer reduces the exposed silver halide crystals to metallic silver, creating the image, while the fixer subsequently stabilizes that image by removing any remaining unexposed crystals. Without this sequence, the film cannot produce an identifiable image, resulting in a completely blank result.