Printing methods used in the label and package printing industry for the production of metallic embellishments with a focus on metal effect pigments

In the label and package printing industry, many methods are used for the application of a metallization on a substrate for graphical purposes. By applying metals like aluminum and copper-zinc on a substrate, outstanding visual effects can be achieved. It is shortly discussed why metallic surfaces appear different compared to non-metallic surfaces and what kind of terms can be used to describe a metallic appearance. Further, different printing methods for metallization are categorized according to the form of the initial metallic material used for the given printing method. It is distinguished between methods using metallic pigments with and without printing ink and metallic foils. Special attention is paid to the printing methods using aluminum pigments in printing ink. The appearance influencing properties of aluminum pigments are listed and different methods of their production are described. The influence of the different ink systems on aluminum pigments and printing methods using these inks are outlined. Furthermore, printing methods using metal effect pigments not incorporated in an ink such as bronzing and the EcoLeaf technology are shortly explained as well as different metallization methods using foil directly involved in the printing process like foil fusing, foil transfer and foil stamping methods.