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.