Lithography

It is an interesting story on how the offset or lithographic process was invented. Back in 1789 a law student at the University of Ingolstadt in Bavaria, Germany, wrote a play entitled “Die Maedchenkenner” and had it published. After printing costs were subtracted, he made a sizable profit and was now convinced his fortune was […]

Lithography – Offset Plate Technology

We have come a long way from the stone plate. As you can well imagine, it would be very difficult to mount a piece of stone on modern high-speed presses. Senefelder’s first press was flat, so the use of stone was easy. Today’s presses use curved cylinders to hold the offset plates. The basis of […]

Lithography – Offset Systems

The conventional offset process contains a plate cylinder, a blanket cylinder and a impression cylinder. A ink and dampening (fountain) system to supply ink and fountain solution is also included. The press prints only one side of the substrate at a time. If you wish to print the other side of the sheet, you must […]

Lithography – Dampening Systems

The conventional or Direct dampening system employs a fountain roller which picks up the fountain solution in the fountain pan. A ductor roller takes the fountain solution from the fountain roller and passes it to a distributor roller. From here the fountain solution is transferred to the offset plate via one or two fountain form […]

Lithography – Ink Systems

The goal of any inking system is to place a uniform layer of ink across every dimension of the printing plate. The Lithographic process is unique in that it requires the ink form rollers to pass in contact with the nonimage areas of the plate without transferring ink to them. All lithographic inking systems are […]

Lithography – Fountain Solutions

Fountain solutions as used on a offset press to keep the ink from adhering to the non-image areas of the offset plate. There are seven key functions of a fountain solution: Keep ink off the background with a film of water Maintain the hydrophilic nature of the background Quickly clean ink off the background during […]

Lithography – Blankets

Offset press blankets are made of supporting fabric and a rubber composite. Various rubber materials are used for the transfer of the image from the plate to the blanket. Blankets come in compressible to hard finishes along with smooth to rough surfaces. The majority of printers today use compressible type blankets. These blankets give good […]

Lithography – Ink Makeup

There are four key ingredients in an ink: Pigments Solvents Vehicles Additives Pigments – These are dry particles that give color to ink. There are various types of pigments such as organic and inorganic. Organic pigments contain carbon and hydrogen and most are made from petroleum. Coal, wood, animal fats, and vegetable oils are also […]