Here's a breakdown of how it works:
* Ionizing radiation: Radioactive nuclides emit different types of radiation, including alpha, beta, and gamma rays. These rays carry high energy and can penetrate materials, including light-proof paper.
* Interaction with silver halide crystals: When ionizing radiation interacts with silver halide crystals in the photographic emulsion, it can knock electrons loose, creating latent image centers. These centers are invisible but represent the potential for a visible image upon development.
* Latent image formation: The latent image centers, formed by radiation, are essentially the same as those created by light. This means that developing the film will reveal an image, even though it wasn't exposed to light.
Consequences:
* Fogging: Radiation exposure can lead to fogging of the film, meaning that the entire film appears gray or hazy, obscuring any real images.
* Artefacts: Depending on the type of radiation and its intensity, the film may show artefacts, such as streaks, spots, or even complete blackening.
* Exposure time: The duration of exposure to radiation directly influences the extent of the effect on the film. Longer exposure times lead to stronger fogging and more pronounced artefacts.
Protection:
While light-proof paper offers protection against visible light, it's not enough to fully shield the film from ionizing radiation. To protect film from radiation exposure, lead shielding is commonly used.
It's important to note that even small amounts of radiation can affect photographic film over time. This is why it's essential to store film in properly shielded containers, especially if it's stored near radioactive sources.
