In X-ray imaging, items containing lead are shown as which color?

• A. White
• B. Gray
• C. Red
• D. Black or dark blue

Answer: (D)

X-ray images represent how much radiation is blocked by each object. Lead is extremely dense and attenuates X-rays very strongly, so on many security or baggage screening displays the areas with the highest attenuation are shown in dark colors. That’s why items containing lead appear as black or dark blue—the color mapping is designed to make dense, metal-containing items stand out. White or gray would generally indicate lower attenuation in this color scheme, and red isn’t used for this purpose in the usual metal-detection color maps.