What is radiation hardness and film contrast?

In this article:

• Radiation Hardness Refers to X-Ray Penetration Power: It is defined by the half-value thickness (HVT)—the material thickness required to reduce radiation intensity by half. Higher radiation hardness means greater penetration and higher HVT
• Increased Radiation Hardness Reduces Image Contrast: As radiation energy increases, the ability to distinguish between different material thicknesses decreases, resulting in lower contrast on radiographic film
• Film Contrast Depends on Radiation Energy and Material Differences: Lower-energy (softer) radiation produces higher contrast images, especially in areas with small thickness variations, as shown in step-wedge comparisons
• Optimal Contrast Requires Balancing Energy and Object Geometry: Selecting the appropriate radiation hardness is critical to achieving sufficient contrast without over-penetrating or underexposing the object
• Tables and Visuals Help Determine Ideal Exposure Settings: Reference tables for steel and lead, along with radiographic images, illustrate how different energy levels affect contrast and guide radiographers in choosing optimal parameters