Flat film and plates are classified under heading 3701 because they are presented in discrete flat sheets or plates rather than wound on a spool or core. Roll film — even if cut from the same emulsion stock — falls under heading 3702. The physical presentation at the time of importation determines which heading applies.

Medical X-ray film may be subject to FDA oversight as a medical device component or accessory. Importers should confirm whether the specific product meets FDA device registration and listing requirements before entry, and consult a licensed customs broker or regulatory counsel for the applicable admissibility pathway.