1. A method for determining an optimal sample dimension suitable for descreening and resealing the raster data of a halftone image, said halftone image converted from an original contone image using a periodic screen, the method comprising the steps of: (a) obtaining parameters of said periodic screen, said parameters comprising: a line density, a cell dimension, and a screen angle; and (b) modifying said cell dimension in response to said line density and said screen angle, thereby calculating said optimal sample dimension suitable for descreening said halftone image.