A radiographic film becomes too dark and fogged, due to:

FILM FOG Improper safelighting (improper filter; excessive bulb wattage; inadequate distance between safelight and work surface; prolonged exposure to safelight) Light leaks (cracked safelight filter; light from doors, vents, or other sources) Overdevelopment  Contaminated solutions Deteriorated film (stored at high temperature; stored at high humidity; exposed to radiation; outdated) White and Pharoah's Oral  Radiology Principles and Interpretation 8th edition