The detection of radiolabeled proteins is of fundamental importance in experimental biology. ³⁵S- and ¹⁴C-labeled proteins can provide investigators with information about protein expression, synthesis, and degradation. Moreover, posttranslational modifications, such as phosphorylation, can be studied with the use of ³²P. Traditional methods for detecting radiolabeled proteins involve somewhat lengthy exposures to photographic film. Quantitation from film-based autoradiography can be achieved by densitometry of repeated and various exposures to films because of the small linear dynamic range of photographic film.