
Autoradiography
Radioactive isotopes release particles, and energy. This reaction, if happening next to a photographic film, will expose it and create spots wherer the reaction has occured.
To see the banding pattern obtained after hybridization, you can place a radioactive membrane in contact with a photographic film, in the dark. After enough time, the film is developed. It will be exposed in the places in contact with radioactivity.
The photographic film is not radioactive.
Pronounce: autoradiograph