Post-printing image development of ink-jet images on non-ink receptive substrates

A method of printing on an ink receptive coating (12) which enhances the density of images printed on non-ink receptive substrates (10) by ink-jet techniques is pro­vided. The substrates, such as transparent polyester films, are coated with a layer of an material to a thick­ness which promotes controlled latent lateral diffusion of the printed ink dots (14a-c). The lateral diffusion is microscopically observed to begin immediately after print­ing, eventually ceasing as the vehicle of the ink is suf­ficiently spread and evaporated by the lateral spreading. The optical density of the image increases as the ink diffuses, reaching a maximum density that is considerably greater than otherwise possible without such an ink-coat­ing system and avoids the undesirable surface coalescence of drops (14) which causes a puddled appearance in films not employing latent spreading. Sheets of such printed imaged media are stored in removable sheet protectors of a vapor permeable, water absorbent material such as cellu­lose acetate, such that dot spread is controlled within the teachings of the invention.