Why are x rays black and white?

The x-ray image is formed when the x-rays travel through the patient onto the cassette. The x-ray cassette is made with a Gelatin, bariums, and crystals the light up when interacted with x-rays. Depending on how much of the x-ray is absorbed by your body, the cassette will light up in different brightnesses, causing certain parts of the film to become slightly exposed. A fully exposed x-ray film will appear black will appear black when processed, while one the hasn't been exposed in any light will show be very light, and only show the color of the film, which has a slight tint, and a properly used x-ray film will show black, white, and different shades of gray depending on the thickness of bones, and tissue mass.