What change will best improve spatial resolution in a radiographic image?

Increasing the source-to-image distance (SID) is recognized as an effective method to enhance spatial resolution in radiographic imaging. When SID is increased, the X-ray beam diverges less by the time it reaches the image receptor, which helps in minimizing the penumbra effect. The penumbra is the area of blurred edges surrounding the image, caused by the geometric unsharpness of the X-ray source size. By maximizing the distance between the X-ray source and the image receptor, the rays converge more narrowly, leading to clearer and sharper images with improved detail of anatomical structures.

The geometry of radiographic imaging indicates that increasing the SID will result in a more focused and defined representation of the subject being imaged, thus enhancing the spatial resolution.

While other options may have particular effects on image quality or different aspects of radiography, they do not directly contribute to improving spatial resolution in the same way that an increased SID does. Reducing OID, for instance, could help improve clarity but is not as impactful on spatial resolution as maximizing the SID.