PPI, or pixels per inch, is a measurement of digital image resolution that indicates how many individual pixels are contained within one inch of an image. Higher PPI values correspond to greater detail, sharper images, and smoother gradations, while lower PPI can result in visible pixelation when the image is enlarged.
In digital photography and scanning, PPI is essential for determining print quality, screen display clarity, and overall image fidelity. Understanding and setting the correct PPI ensures that images maintain their intended sharpness, colour accuracy, and detail whether viewed on monitors or reproduced in print.