When an x-ray film is over-exposed and excessively blackend as in Figure 1a and 1b, it is very difficult to recognize not only pathologic changes but also normal features. One of solvents such as xylene or acetone is widely used to rub out stained dust, ink or colored wax on x-ray films. However, if the detaills of an over-exposed x-ray is sealed by blackening, these solvents are of no use. Under such a circumstance, sodium hypochlorite (NaCIO) has its place in attenuating the film density and thereby improving the image quality by removing blackened silver bromide. This chemical agent is contained richly in bleaching solution which is obtainable with ease. Sodium hypochlorite reacts with silver bromide of the photographic emulsion and results in the formation of silver chloride which precipitates. In this way, excessive photographic emulsion from one of the two sides of an x-ray film can be removed with resultant attenuation and improvement of the image quality as in Figure 1b and 2b.