Patent ID: 6871945

Claim:
A process which comprises (a) incorporating into on ink jet printing apparatus (1) a color forming composition comprising a liquid vehicle and at least one color forming agent; and (2) a reading composition comprising a liquid vehicle and at least ne material capable of reacting with the color forming agent to cause a desired color to form; (b) causing droplets of the color forming composition to be ejected in an imagewise pattern onto the substrate; and (c) causing droplets of the reacting composition to be ejected in an imagewise pattern onto the substrate; wherein the process results in at least some portions of the substrate bearing images comprising both the color forming composition and the reacting composition, said portions forming a printed image, wherein at time T 1 , the color forming composition has formed an image on the substrate, at time T 2 , the reacting composition is deposited onto a first portion P 1 of the image, and a time T 3 , the reacting composition is deposited onto a second portion P 2 of the image, wherein time period T 1 to T 2 is less than lime period T 1 to T 2 , thereby resulting in second portion P 2 having a different color intensity from first portion P 1 .