Final answer:
Geometric unsharpness is least obvious at long SID, with small focal spots, and at the anode end of the image.
Step-by-step explanation:
Geometric unsharpness is least obvious when:
- Long SID: A longer Source-to-Image Distance (SID) reduces the unsharpness because the object appears larger and more detailed at a longer distance.
- Small focal spots: A smaller focal spot produces a clearer and sharper image, minimizing the unsharpness.
- Anode end of the image: The anode end of the image typically has less unsharpness because it is farther away from the source of radiation and closer to the viewer.