This is sometimes also called thermal transfer overprinting (TTO). In this technique, the ink from an ink ribbon is transferred or melted onto the printing medium (e.g. paper or film) by means of heat. It is mainly employed in situations in which it is necessary to produce labels that have stringent requirements in terms of printed image quality, durability and flexibility of the label material, paper labels, plastics, textiles and metallic surfaces, etc., can be printed in this way. The best and most durable printed results are achieved on labels using thermal transfer printing, meaning that the technique is particularly suitable for printing barcodes and variable information.