An X-ray is a high frequency, high energy wave form. It cannot be seen with the naked eye, but can be picked up on photographic film. Although you may think of an X-ray as a picture of bones, a trained observer can also see air spaces, like the lungs (which look black) and fluid (which looks white, but not as white as bones).
Was this page helpful?
This page was last updated at 12:26PM on May 12, 2014. This information is reviewed and edited by X-ray.