1. A method of preparing a security document comprising the steps of: designating a security image area on the face of a document; dividing said security image area into a plurality of image element cells, such that said image element cells define an array of image element cells across said security image area; dividing each of said image element cells into a plurality of pixels, such that each image element cell defines a cell pixel array; establishing a set of active image element cells, wherein said set of active image element cells defines a security image; positioning a pixel cluster within each of said active image element cells such that at least a portion of said pixel cluster is positioned within said active image element cell, wherein the position of said pixel cluster within each of said active image element cells is designated on a substantially random basis, and wherein each of said pixel clusters defines a predetermined image element; establishing a complementary security image within said security image area, wherein said complementary security image is formed by a set of predetermined complementary image elements; and printing a security document including printed areas corresponding to said predetermined image elements and said complementary image elements.