Density is the degree of darkness on a radiographic image; contrast is the difference in shades of gray on an individual radiographic image.

• A. Both statements are true
• B. The first statement is true and the second is false
• C. The first statement is false and the second is true
• D. Both statements are false

Answer: (A)

Density describes how dark the radiographic image appears, which depends on how much radiation reaches the film and produces dark silver deposits. Contrast describes how different the gray tones are between adjacent structures, i.e., how easily you can distinguish neighboring densities.

These are separate ideas: density is the overall darkness, while contrast is the range of gray shades that separates structures. The statement that density is the degree of darkness and that contrast is the difference in shades of gray on a single image matches standard definitions, so both statements are true. In practice, density changes with exposure factors and subject thickness, and contrast changes with kVp and processing, but the basic meanings remain.