What is lithographic printing?

Lithographic printing, also known as lithography or planography, is a type of printing that is based on the basic concept that water and oil are immiscible liquids. Here, the imaged and non-imaged areas are on a single surface, unlike in the case of intaglio and relief printing, where they are on different levels, with the imaged area being higher than the base non-imaged area. Lithography is regarded as a traditional and definitive medium for high capacity printing.

The high-quality results of lithographic printing come from a unique and complex operational process that begins with the coating of a light-sensitive emulsion on the printing plate. The transfer of the image to the plate is done in several ways. One technique is to place the film on the plate and then expose it to light. The second way to do this is by using machines that expose the plate using lasers. In either case, detailed formation of the negative of the image to be printed takes place. The emulsion that was coated in the first step is then released and thus a positive image of the image is printed. Unexposed areas are then removed by chemical treatment.

Lithographic printing is the most versatile and unrestricted printing process today. It is the first choice among artists, as it allows them the freedom to use any type of medium: pens, oils, pencils, crayons, etc. and be able to create works of art with the same impact.

Commercially, the application of lithography works differently where instead of a stone plate, metal plates are used. Mounting metal plates on lithographic presses is relatively much easier and this factor has made lithographic printing viable for mass production. For commercial applications, lithographic printing takes the form of photolithographic printing in which a photographic negative of the image to be printed is placed on a gelatin-coated paper and exposed to light. The areas where the gelatin is exposed to light become insoluble while the remaining areas are left soluble. The soluble areas are then washed away and the image to be printed is inked and transferred to the plate. Lithography has a wide commercial scope and can be applied in various ways.

Lithographic printing turns out to be the best and cheapest printing option if you need a large number of prints. Here, the printing plate once made, cannot be edited. These printers may not be used for any type of digital printing involving computers. They are used primarily by commercial printers for quality purposes.