You are now entering the PC Anatomy portal

In computing, grayscale is a range of achromatic colors composed of shades of gray, ranging from pure black to pure white. A grayscale image contains only information about the intensity or brightness of each pixel, rather than color data.

How grayscale images work

Single-channel storage: While color images typically use three channels (one each for red, green, and blue), a grayscale image is stored as a single channel. Each pixel is assigned a single value that represents its intensity or luminance.

Numerical representation: For a common 8-bit grayscale image, each pixel is assigned an integer value from 0 to 255.

Bit depth: The number of gray shades available is determined by the image's bit depth. An 8-bit image offers 2\({}^{8}\), or 256, shades of gray. A 16-bit image offers 2\({}^{16}\), or 65,536, shades, providing finer tonal gradations.

Distinction from black-and-white: A grayscale image is not the same as a bi-tonal (or 1-bit) black-and-white image, which only contains two colors—black and white—with no intermediate gray tones.