Final answer:
A high grid ratio implies a narrow focusing range which is beneficial for reducing scatter and improving image contrast in radiographic imaging, but requires precise alignment to avoid grid cutoff.
Step-by-step explanation
A high grid ratio corresponds to a focusing range that is narrow. This means that the grid is designed to allow X-rays traveling in a specific, narrow range of angles to pass through to the image receptor, while absorbing or scattering X-rays that do not align with these angles. This helps to improve image contrast by reducing the amount of scatter reaching the detector. A high grid ratio is more effective in scatter reduction but requires more precise alignment between the X-ray tube, the patient, and the image receptor. Using the higher ratio grid outside of its narrow focusing range can introduce grid cutoff, leading to the loss of image information.