A method for preparing a PCB product having highly dense conductors, the method comprising: providing a PCB substrate including a conductive copper layer ; employing an inkjet printer to selectively print unexposed photosensitive patterns on said PCB substrate , said unexposed photosensitive patterns having a thickness of less than 5 μm; exposing said photosensitive patterns to radiation thereby to define exposed patterns, said exposed patterns having a pitch less than 20 μm; and wet etching said conductive layer in accordance with a pattern defined by said exposed patterns thereby to define said highly dense conductors having a pitch of less than 30 μm; and wherein said unexposed photosensitive patterns are printed with a photosensitive ink comprising: a photoresist constituting 33 - 64 wt. % of said photosensitive ink; a solvent constituting 19.99 - 59.99 wt. % of said photosensitive ink; a humectant constituting 1 - 10 wt. % of said photosensitive ink; a surfactant constituting 0.01 - 0.1 wt. % of said photosensitive ink; an adhesion promoter constituting 1 - 3 wt. % of said photosensitive ink, said adhesion promoter having a molecular weight between 8000 - 70000 Da and being operative to increase anisotropy of the wet etching process of a copper component on which the photosensitive ink is printed; and a basic solution constituting 2 - 3 wt. % of said photosensitive ink, said adhesion promoter being dissolved in said basic solution. providing a PCB substrate including a conductive copper layer ; employing an inkjet printer to selectively print unexposed photosensitive patterns on said PCB substrate , said unexposed photosensitive patterns having a thickness of less than 5 μm; exposing said photosensitive patterns to radiation thereby to define exposed patterns, said exposed patterns having a pitch less than 20 μm; and wet etching said conductive layer in accordance with a pattern defined by said exposed patterns thereby to define said highly dense conductors having a pitch of less than 30 μm; and wherein said unexposed photosensitive patterns are printed with a photosensitive ink comprising: a photoresist constituting 33 - 64 wt. % of said photosensitive ink; a solvent constituting 19.99 - 59.99 wt. % of said photosensitive ink; a humectant constituting 1 - 10 wt. % of said photosensitive ink; a surfactant constituting 0.01 - 0.1 wt. % of said photosensitive ink; an adhesion promoter constituting 1 - 3 wt. % of said photosensitive ink, said adhesion promoter having a molecular weight between 8000 - 70000 Da and being operative to increase anisotropy of the wet etching process of a copper component on which the photosensitive ink is printed; and a basic solution constituting 2 - 3 wt. % of said photosensitive ink, said adhesion promoter being dissolved in said basic solution. a photoresist constituting 33 - 64 wt. % of said photosensitive ink; a solvent constituting 19.99 - 59.99 wt. % of said photosensitive ink; a humectant constituting 1 - 10 wt. % of said photosensitive ink; a surfactant constituting 0.01 - 0.1 wt. % of said photosensitive ink; an adhesion promoter constituting 1 - 3 wt. % of said photosensitive ink, said adhesion promoter having a molecular weight between 8000 - 70000 Da and being operative to increase anisotropy of the wet etching process of a copper component on which the photosensitive ink is printed; and a basic solution constituting 2 - 3 wt. % of said photosensitive ink, said adhesion promoter being dissolved in said basic solution. <EOS>