An X-ray of the abdomen is a safe and painless test to visualise the organs of the abdomen which includes the stomach, intestine, gall bladder, base of the lungs, liver and spleen. When it is specifically used to visualise the kidney, ureter and bladder, it is called KUB X-ray. The image is recorded on a special X-ray film. The X-ray image is black and white. Dense structures such as the bones, appear white and softer body tissues, such as the skin and muscles appear darker. The actual exposure time to radiation is usually less than a second, although the overall test may take 15-20 minutes.