Offset printing is a technique of printing in which the image that is linked is transferred to a rubber blanket from a plate. Later it is transferred back to the surface of the printing. When it is used in fusion with the lithographic process that is based on the repulsion of water and soil, a flat image carrier is employed by the offset technique. Ink rollers then transfer ink to the areas of the image carrier, while a water-based film is applied by a water roller to the non-image areas.
The modern process is also known as the “web” process feeds a huge reel of paper through a big press machine for several meters, typically in several parts which print continuously as the paper is fed into the machine.
MODERN OFFSET PRINTING
One of the most important functions in the process of printing is prepress production. This stage ensures that all the files are processed correctly for printing preparation. This includes converting into the proper color model of CMYK, creating plates for every color of the job, and finalizing the files to run on the press. Offset lithography or printing is one of the most common ways to make printing materials.
Some common applications of Offset printing are books, stationery, brochures, magazines, and newspapers. Offset printing is best suited for producing high-quality prints in large volumes in a manner that needs a little maintenance. Many Offset that are modern use systems that are computer to plate as opposed to the computer to film workflows that are older, which increases their quality.
There are mainly 2 types of offset printing that are waterless offset and wet offset. Wet offset lithography uses wet fluids mix or dampening solutions to manage the adhesion of ink and protect non-image areas. Waterless offset lithography uses a different method where non-image areas of the plate are protected via an ink-repellent silicon layer. Waterless offset lithography is considerably new.
ADVANTAGES OF OFFSET PRINTING
Offset printing generates consistent high-quality images. It produces clean and sharp images and types easier than other printing like letterpress printing, this is because the blanket of rubber conforms to the texture of the printing surface. It is easy and quick in producing printing plates. Offset printing has a longer life on printing plates than on litho presses because there is no contact between the surface of the printing and the plate. The plates that are properly developed are used with fountain solution and optimized inks. It can achieve a running length of more than a million impressions.
If we talk about cost then it can beat most of its competitors as Offset printing is the cheapest method that is used for producing prints of high quality in quantities of commercial printing. It also has the ability to adjust ink’s amount with screw keys on the fountain roller. The operator adjusts the gap between the fountain roller and the blade, decreasing or increasing the ink’s amount in certain areas of the roller. This modifies according to the color’s density in the respective area of the image.
On older machines, someone has to adjust the screws manually but on modern machines, the screw keys are electronically operated by a printer controlling the machine, enabling a result that is much more precise. Every printing technology has its own marks of identification and offset printing is no exception. The types have clear outlines and are sharp in text reproduction. The ink dots that are surrounded by the paper are usually unprinted. There are different screening methods though the halftone dots can be hexagonal.
THE FUTURE OF OFFSET PRINTING
Offset printing is one of the most broadly used techniques of printing in the whole world. Due to high-quality printed products and the low price of the print, it is used in packaging production, the printing of labels, commercial printing, and other printed products. The history of offset printing is linked to stone printing or lithography. Lithography printing is a technique of direct printing that means the printing medium and printing form are in direct contact during the printing process.
he technology of Offset printing has changed over the past some years, even though the printing’s physical principle is identical. The most commonly used printing form these days is an aluminum plate from 15 to 70 microns thick coated with a layer that is photo-sensitive. In the beginning, getting the printing form was a completely symmetrical process. The digitalization of preparation and photographic processes was used in a film that was illuminated digitally on computer-to-film or CTF devices. In this way, separation of color was transmitted and obtained by the subsequent process of lighting to the printing plate.
The printing plate is created by direct illumination these days on a computer-to-plate or CTP device. Thus, the printing plate that is developed is mounted in the printing machine on the plate cylinder. There is a complex cylinder system (impression, blanket, and plate) and rollers for inking and wetting that is synchronized with the transport transferees of the ink on the substrate of printing. With the media’s transport (paper, cardboard, etc.) on which the pattern is printed, a color print is obtained throughout four basic units of printing (CMYK). The offset printing machines that are modern have basic CMYK inks along with more than four units in the series, units for more colors like Pantone colors or units for varnishing are often used, which increases the prints’ gamut or according to the wishes of the customer, someone can print a color that is specific.
Today the printed materials’ share in the world by offset technology is around 40 to 45%. The share of this technology previously was around 50% at the time of world war. But it got replaced by other technologies such as flexo printing. The future of offset printing is bright as most people prefer it by the looks of the printed material and it will stay here for a long time.