Grayscale
An image format that contains only brightness information, representing tones from black to white without any color data.
Grayscale is an image representation that uses only luminance (brightness) values without hue or saturation. An 8-bit grayscale image contains 256 shades ranging from pure black (0) to pure white (255). Since it stores only one channel instead of three, file sizes are roughly one-third of equivalent color images.
Converting a color image to grayscale involves weighting the RGB channels according to human visual perception. The standard formula is luminance = 0.299R + 0.587G + 0.114B, with green weighted highest because human eyes are most sensitive to green light.
Grayscale conversion is easily done with the image conversion tool. Common uses include creating artistic monochrome photos and reducing file sizes for scanned documents. Combining with contrast adjustments produces more striking results.