NAVTA Canvas Practice Exam - Prep, Study Guide & Full Practice Test

In radiography, the appearance of an object's density on a radiograph is determined by how much x-ray radiation it absorbs or allows to pass through. Dense materials, like bones or metal, absorb more x-rays and therefore appear lighter or white on the image. Conversely, materials that are not dense, such as air or some soft tissues, allow x-rays to pass through more freely.

When x-ray beams pass right through an object, that object does not attenuate the x-rays, resulting in a darker appearance on the radiograph. This is why areas that are less dense or completely transparent to x-rays will show up as black. The black areas reflect high levels of radiation exposure, indicating that the x-rays were not absorbed by the material in question, but instead passed through and reached the film or detector. This is a fundamental principle in interpreting radiographs.