Not infrequently overexposed or underexposed x-ray films impose difficulty in interpretation necessitating repeated radiography. However, repeated examination is not always possible because of the transfer, discharge, and dying of the patients. Then, retonning of improper films is much desirable expecially when such films are of considerable clinical and academical importance. The authors carried out a series of experiment to improve the tone of the overexposed and underexposed x-ray films by different exposure times. during duplicating the overexposed film, the film density became bright and imaging details were improved by increasing the exposure time. Underexposed film, however, did not showing any improvement of imaging details but darkened only of overall film density. Therefore, qualified reproduction of overexposed x-ray film using the x-ray film duplicator was easy to do and valuable in the management of film quality without any damage to the original film.