As the grid ratio decreases, what happens to the scale of contrast in radiographic images?

When the grid ratio decreases, the scale of contrast in radiographic images decreases. This is because a lower grid ratio allows more scattered radiation to reach the film or detector, which reduces the overall contrast in the image. High grid ratios are designed to absorb more scatter, enhancing the difference between the various densities on the image, leading to a higher contrast. Conversely, with a lower grid ratio, there is less capability to absorb scatter, resulting in a more uniform density across the image.

This means the difference between the light and dark areas becomes less pronounced, which effectively translates to a decrease in the scale of contrast. Therefore, when using lower grid ratios, one can expect a radiographic image that has a wider range of intermediate grays instead of sharp black and white differences.