gray-scale gradient

Quick answer：

Gray-scale gradient refers to a gradual transition from one shade of gray to another. It is commonly used in design, photography, and art to create a sense of depth, perspective, or to blend colors smoothly. In digital media, it is often achieved by adjusting the brightness and contrast of an image or by using gradient filters. In painting or printing, it involves mixing different shades of gray paint or inks to create a seamless blend.