What is the useful optical density (O.D) range for radiographs?

The useful optical density (O.D) range for radiographs typically falls between 0.5 and 2.5. This range is significant because it encompasses the density levels at which radiographs provide adequate contrast and detail necessary for interpretation. An O.D. of 0.5 indicates a lighter area, while an O.D. of 2.5 indicates a much darker area. This range allows for a balance between visibility of structures and clarity in distinguishing between different materials or defects in the object being examined.

When the optical density falls below 0.5, the images might be too light, making it difficult to discern important details. Conversely, densities above 2.5 can lead to overly dark images where critical information may be obscured, hindering effective analysis. Thus, maintaining the optical density within the 0.5 to 2.5 range is crucial for producing radiographs that are diagnostically useful and effective for radiographic examinations.