A method of printing an interface onto a surface, the interface including visible text/graphics and coded data, the coded data being indicative of an identity of a region of the surface and of a plurality of locations on the surface, the method comprising the steps of: (a) providing a printer comprising: a data input module for receiving document data from a computer system, the interface being based at least partially on the document data; a coded data generator for generating the coded data using at least some of the document data; a printhead for printing the interface onto the surface; and an ink supply for supplying ink to the printhead, the ink supply comprising an ink set including at least one visible text/graphics ink and a coded data ink; and (b) printing the visible text/graphics and the coded data onto the surface using the printer, wherein the or each visible text/graphics ink has an absorption of less than 20% at all wavelengths in the range of 800 to 900 nm, where 100% absorption is defined as the maximum absorption of the or each visible text/graphics ink when printed onto the surface.