1. Image editing apparatus, comprising processing means, input means and selection means; wherein a source frame comprising a foreground image against a background of a substantially uniform backing color is provided to said processing means via said input means, wherein said source frame is composed of a plurality of pixels, each pixel being represented by three components defining a position within a color space; wherein said processing means is configured to: (a) calculate a transformation that maximises a distance value of a selected pixel in the background, which transformation when applied to any pixel in said source frame defines a corresponding transformed pixel, wherein for any pixel said distance value describes how close its color is to a specified color; (b) calculate a transparency value for each pixel in the source frame, wherein for each said pixel said transparency value is a function of the distance value of the corresponding transformed pixel; and (c) for each pixel in the source frame, multiply the components of said selected background pixel by the transparency value of the source frame pixel and subtract the results from the components of the source frame pixel to color-suppress said source frame.