Why is it that sometimes when bones are x rayed they appear as white images?

Answer 1

Bones always appear as white images in regular xrays. However they arent really white because the film is clear, the plastic on the view box is white. But on xray film it is coated with a metalic layer. The xrays make the metalic layer stick to the film. So the black part of the film is where all the xrays reach the film. If the area on the xray is gray, then that means that some of the xrays are getting through implying that the structure is more dense than the black part. Soft tissue appears gray. The bone is a very dense structure allowing minimal to no xrays getting through. The film is then put through the processor and the film runs through chemicals that make the picture "stay" on the film. It is then rinsed and dried. Since the xrays make the metalic layer stick, none stick to the area of the bone because no radiation got through and the layer was washed off during processing. This is why bones appear white, they are the densest structure.