Offset printing is the most preferred printing technique that has been used for over a century. It provides the opportunity to print thousands of materials quickly.

What is Offset Printing? What is its Working Principle?

Offset printing is a printing technique used to print images on the paper surface. It can be applied to many papers or similar materials of a certain weight and size, from business cards to giant billboard brochures. It is a printing technique that is very common today. It is a preferred method in printing systems that require a lot of printing at the same time like newspapers. We can see offset printing applications in thousands of materials that we can encounter in business and in our daily lives.

Unlike other printing techniques, the surface to be printed and the surface to be printed are also called “flat printing” or “indirect printing” since they are of equal height. Its English is “offset” and it is translated to Turkish as “offset printing”, inspired by this word.

What is Offset Printing?

The name of the offset has been changed from the “OFF-SET” word pattern in English to Turkish and enables printing on paper and paper-like material up to a certain weight. Today, it is the most preferred printing system in the printing of products such as books, magazines, newspapers, brochures and business cards. Especially since many products can be printed at the same time, the preferred method of printing daily newspapers is offset printing.

In offset printing, one of the newest printing techniques, the visual desired to be printed is drawn on a limestone whose surface is flattened with an oil-based ink. A special solution applied after this process is absorbed by the places where the visual is not located and does not penetrate the oily areas that make up the image.

In offset printing, which is a flat printing technique, manually prepared or fabricated dies are used. Although the cost is slightly higher in fabricated molds, the quality is higher than the hand-molded molds. In other words, preferring fabricated molds in offset printing provides higher quality printing.

Working Principle

Although it is a printing system developed late due to its advantages such as low cost and high printing speed, offset printing is the most commonly used printing system in the world today.

This printing system is based on the principle of “water not mixing with oil-based ink”. In the printing mold used, it is also called as “flat printing system” or “indirect printing system” because the parts to be printed and parts not to be printed are of equal height. The surface of the molds used in this printing system and made of different metals is covered with a substance called enamel, which is extremely sensitive to light. This substance named Enamel holds ink and repels water. For this reason, it is of great importance in the offset printing system.

The offset printing machine can print in color at once because it has a separate printing unit for each color to be printed. It is used to obtain blue, red, yellow and black, all other colors. The printing paper to be used goes through these color units.

The transfer function roller used in the printing process is called blanket in the printing jargon. The blanket, which has a flexible structure, performs the stretching action while it is pressed on the paper and therefore it is in contact with both the paper and the printing mold.

On the other hand, the mold touches both the water and the ink roller, and the ink takes the water to the place where the ink will not be printed. The enamelled areas we just mentioned are transferred to the blanket after the ink is removed after receiving the ink. The ink in the area to be printed is flat on the die, but passes across the blanket. Then this reverse image on the blanket is printed flat on the paper that passes between the printing boiler and the blanket boiler, and the printing process ends in this way.

Offset printing types

Offset printing is divided into two main branches. These are sheet offset printing and web offset printing.

Sheet Offset Printing: As the name suggests, it is an offset printing type using sheet paper as the printing material. It has derivatives that can print in sizes from 25 × 35 cm to 70 × 100 cm. Newspapers, magazines, books, etc. It is suitable for printing. There are two, four, five, six, eight, ten, twelve color press variants available.

Web Offset Printing: It is a kind of offset printing using bobbin papers. It is a printing type that has high speed and low cost compared to offset. It is used in today’s newspaper and magazine printing works.

If you want to watch how the offset printing system works, you can click the link below and watch the related video.