1. A method of modifying image data, the image data comprising a luminance signal and a chrominance signal for each of a series of pixels forming an image, comprising the steps of: for each pixel in the image, calculating an edge behavior value, the edge behavior value being related to an amount of change in luminance signals among a neighborhood of pixels near said pixel; for each pixel in the image, calculating a revised chrominance value according to a chrominance revising algorithm, the chrominance revising algorithm including as inputs a chrominance signal for at least one pixel in the neighborhood of said pixel, and the edge behavior value for said pixel, restricting the revised chrominance value for said pixel to a range between a maximum and minimum chrominance signal of said neighborhood of pixels near said pixel; and for each pixel in the image, substituting the revised chrominance value for a chrominance signal of said pixel.