Interpolation is a technique used to mathematically increase the apparent resolution of an image. Interpolation increases image resolution by adding more pixels and then colors the new pixels using an average of the colors in the surrounding pixels. This may reduce the jagged appearance at the edges of the image, but it may also make them fuzzier. Interpolation results in higher resolution, but color purity can be compromised and is often visible when magnified.

Interpolated resolution is much higher than the optical resolution. For example, a scanner with an optical resolution of 600 x 1200 ppi might have an interpolated resolution of 9600 ppi.