A method for producing a document (500, 700) having a document body and a visually imperceptible security feature connected to the document body, said method comprising: - providing an inkjet printer which includes at least a first tank containing a dye-based ink and a second tank containing a pigment-based ink, wherein the absorption spectrum of the dye-based ink and the absorption spectrum of the pigment-based ink are so similar to one another that an inkjet print with the dye-based ink and an inkjet print with the pigment-based ink are indistinguishable to the human eye under illumination by light in the visible spectral range; - providing a digital graphical pattern which is formed from one or more first areas (408.1, 408.2) and one or more second areas (406.1, 406.2); and - providing a digital image to be connected to the document; - superimposing the graphical pattern and the digital image; - providing the document, wherein the thickness of the document specifies its spatial extent in a dimension z, wherein the document body consists of a plurality of material layers; - printing the digital image onto the or into the document body by means of the inkjet printer in such a way that the dye-based ink, but not the pigment-based ink is used for printing the regions (414.1, 414.2) of the digital image superimposed with the first areas, and in such a way that the pigment-based ink, but not the dye-based ink is used for printing the regions (412.1, 412.2) of the digital image superimposed with the second areas, wherein the distribution of the dye-based ink and the pigment-based ink in the printed image is the security feature, wherein the one or more regions (414.1, 414.2) superimposed with the first areas (408.1, 408.2) contain first inkjet droplets and are free of the second inkjet droplets, wherein the regions (412.1, 412.2) superimposed with the second areas (406.1, 406.2) include second inkjet droplets and are free of the first inkjet droplets, wherein the first inkjet droplets (720, 722) have a first morphology and consist of the dye-based ink, wherein the second inkjet droplets (716, 718) have a second morphology, which differs from the first morphology, and consist of the pigment-based ink, wherein the first and second areas form the pattern, which, under illumination by light in the visible spectral range, is not perceptible to the human eye, - wherein at least some of the inkjet droplets extend over a plurality of the material layers, wherein a topology of an inkjet droplet describes its spatial extent over one or more of the material planes in the dimension z; and - wherein the topology of the first inkjet droplets differs from the topology of the second inkjet droplets. - providing an inkjet printer which includes at least a first tank containing a dye-based ink and a second tank containing a pigment-based ink, wherein the absorption spectrum of the dye-based ink and the absorption spectrum of the pigment-based ink are so similar to one another that an inkjet print with the dye-based ink and an inkjet print with the pigment-based ink are indistinguishable to the human eye under illumination by light in the visible spectral range; - providing a digital graphical pattern which is formed from one or more first areas (408.1, 408.2) and one or more second areas (406.1, 406.2); and - providing a digital image to be connected to the document; - superimposing the graphical pattern and the digital image; - providing the document, wherein the thickness of the document specifies its spatial extent in a dimension z, wherein the document body consists of a plurality of material layers; - printing the digital image onto the or into the document body by means of the inkjet printer in such a way that the dye-based ink, but not the pigment-based ink is used for printing the regions (414.1, 414.2) of the digital image superimposed with the first areas, and in such a way that the pigment-based ink, but not the dye-based ink is used for printing the regions (412.1, 412.2) of the digital image superimposed with the second areas, wherein the distribution of the dye-based ink and the pigment-based ink in the printed image is the security feature, wherein the one or more regions (414.1, 414.2) superimposed with the first areas (408.1, 408.2) contain first inkjet droplets and are free of the second inkjet droplets, wherein the regions (412.1, 412.2) superimposed with the second areas (406.1, 406.2) include second inkjet droplets and are free of the first inkjet droplets, wherein the first inkjet droplets (720, 722) have a first morphology and consist of the dye-based ink, wherein the second inkjet droplets (716, 718) have a second morphology, which differs from the first morphology, and consist of the pigment-based ink, wherein the first and second areas form the pattern, which, under illumination by light in the visible spectral range, is not perceptible to the human eye, - wherein at least some of the inkjet droplets extend over a plurality of the material layers, wherein a topology of an inkjet droplet describes its spatial extent over one or more of the material planes in the dimension z; and - wherein the topology of the first inkjet droplets differs from the topology of the second inkjet droplets.