What does a longer gray-scale contribute to in an image?

A longer gray scale contributes to decreased contrast in an image. This is because a longer gray scale represents a broader range of tones between the darkest and lightest areas. When more shades of gray are present, it allows for a smoother transition between different tonal values, which can create a more subtle image with less distinction between highlights and shadows.

This means that with increased gray scale range, the differences in apparent brightness between adjacent tones become less pronounced, leading to an overall softer appearance in the image. In contrast, a shorter gray scale would yield a more limited range of tones, resulting in higher contrast, as the differences between shadows and highlights would be more significant and visually distinct.