Which type of grid error occurs when the central ray is not aligned to the middle of the focus grid?

When the central ray of the x-ray beam is not aligned with the center of a focused grid, an off-center grid error occurs. This misalignment can lead to a loss of image contrast and potential image artifacts, as the grid is designed to allow only x-rays that travel directly through its focal area to reach the detector. When the central ray is off-center, it compromises the grid's ability to absorb scattered radiation effectively, resulting in an uneven density across the radiographic image.

In this context, understanding the specific nature of this error helps radiologic technologists ensure proper alignment and enhance the quality of diagnostic images. By recognizing that the central beam must be properly centered on the focus grid, professionals can avoid common pitfalls that diminish image clarity and diagnostic utility.