Lithography leaves behind a smooth finish to the printed surface, unlike letterpress or gravure printing which leaves impressions and rings in the printed ink. This style of printing is also very versatile and used to print anything from catalogs, posters and advertising leaflets to newspapers, books and magazines.
The process of printing in this style has changed from the original presses, where the ink was transferred directly from the plate to the paper. Modern techniques are known as “offset” lithography as the image is transferred from the plate to a rubber roller (known as the blanket) and then onto paper. The image can either be etched onto the plate, or created using light sensitive emulsion. With the light sensitive emulsion, the whole plate is coated with the emulsion, then a film with the negative of the image is laid over the plate, which is then exposed to light (often using lasers), which causes the emulsion exposed to light to change colour, releasing coloured ink. The ink transfers to the rubber blanket when it is rolled over the plate, which in turn is rolled over the paper, to reveal the image.
Modern lithography presses have been developed to print on both sides of paper at the same time, making them ideal for use in the media industry. Some presses have been developed to print on substrates other than paper, such as fabric and plastics. Lithography may have been developed in the past, but it is certainly a technique adaptable for the future!