Gray-scale is fundamentally defined as:

Gray-scale is fundamentally defined as the total brightness levels that are visible in an image. This definition captures the essence of gray-scale imaging, which displays a continuum of gray shades from black to white. In a gray-scale image, each pixel is assigned a brightness value, typically ranging from 0 (black) to the maximum value (which represents white). This total range of brightness levels allows for varying intensities of light, resulting in a richer representation of depth and form without the inclusion of color.

Understanding gray-scale as referring to brightness levels is essential for evaluating images in terms of contrast and detail, as these aspects heavily rely on how light and dark areas interact. This comprehension underpins various applications in imaging techniques, photography, and medical imaging, where distinguishing subtle variations in brightness can be crucial for accurate interpretation and analysis.