There are five perceivable degrees of inherent radiopacity they are:
         
 
 
 

Air (in the bladder)

Fat (around intestines)

Sof tissue (the kidney)

Bone (pedal bone)

Metal (x-ray marker,R)

These shades of black to white  depend on the atomic number of the tissues and their thickness.   Thickness also determines the appearance of overlapping opacities. Two bones that cross will appear whiter where they cross due to greater thickness. Total radiopacity depends on thickness and inherent radiopacity.

Back