X-Ray testing is the best nondestructive inspection method for detecting internal defects of castings can be examined to verify the internal structure and integrity of the specimen.The casting absorbs part of the radiation, and the remaining portion of the radiation exposes the radiographic film. Dense material withstands the radiation penetration, so the film is exposed to a lesser degree in those areas, giving the film a lighter appearance. Less dense materials allow more penetration and correlates to darker areas on the film. Any hole, crack or inclusion that is less dense than the casting alloy is revealed as a dark area.