Because wood is a porous material it absorbs ink well. This makes the use of oil based inks possible. It is important to use UV resistant inks with extra dye for this, coding will then also remain clearly visible after prolonged exposure to moisture or sunlight. If for example pressed wood with an extra open structure is to be printed alternatively also solvent based inks can be used. The solvent will evaporate quickly before the ink gets a chance to start running or smudge.
The coding of wood is predominantly done by Hi-Res Inkjet. The wood is then transported past the print head and coded on the production line (or straight from the sawing machine). Intelligent sawing machines can then directly communicate to the printer what to print (like measurements or batch numbers). Depending on the required print resolutions, very high speeds at high resolution are possible. For non variating and/or small codings, Rollcoders and Hot solid Inks are also quite suitable for use to code on wood.