The HP Indigo printing process is known for matching offset lithography's print quality and its application versatility, with the ability to print on a wide range of materials. It uses a proprietary printing process called Liquid Electrophotography, or LEP for short, which is similar to the process used in laser printers, but with special electrostatically charged inks instead of toner, and without using a fuser, using instead a heated transfer roller to melt the charged ink particles before applying them to the paper. Up to seven inks, including the standard CMYK plus a wide range of spot colors and metallic colors, can be used simultaneously on a single press, thereby providing an extended color gamut. The user can also custom-mix, load, and interchange inks as desired. Inks can be laid down in any order desired, and multiple layers of each ink are also possible.