Anodised underprinting is nowadays also possible by means of the digital anodised underprinting process, in which the ink from different ink cartridges is automatically mixed and applied under pressure into the open pores of the print medium using a print head with several thousand nozzles. The ink seeps into the open pores and dries, which means that the pore geometry is decisive for the subsequent print image. Roughly speaking, the digital anodised underprinting process is the same as for an inkjet printer, except that aluminium with open pores is used instead of paper. After drying, the open pores are closed again by a chemical treatment under the influence of high temperature, the so-called compaction or sealing.
If the process is finished, it is called anodised underprinting or digital anodised underprinting which is largely scratch and solvent-resistant. Since the ink is embedded in the anodised layer in the first 8 to 10 µm.