Abstract: An ink jet printing method is provided which method comprises the steps of:(1) image-wise protecting by means of an ink jet a liquid, called ink, in the form of droplets onto a receiving material containing at least one reagent A that with at least one reagent B contained in the ink droplets is capable of forming by color reaction a colored product, and(2) optionally uniformly heating said receiving material and/or uniformly exposing it to chemically active electromagnetic radiation during and/or after the deposition of said ink on said receiving material to start or enhance said color reaction, characterized in that from separate ink jets ink of different concentrations of said at least one reagent B or inks containing separately reagents A or B in different concentration is (are) deposited image-wise onto said receiving material containing said at least one reagent A.