We can define a printing system as a way of reproducing an image on a physical support such as paper or textile. We have been printing ink on paper for more than 500 years with the advent of the printing press. All printing systems have been evolving with us, but when we talk about printing an image on a paper surface, there are 3 most important printing models today.
We are talking about offset printing, digital printing and screen printing. Let’s review exactly what each one consists of, what their advantages and differences are.
Which printing systems are most appropriate for me?
Knowing the different printing systems is a fundamental task for all of us who are going to work in the graphic arts sector. It will help us to efficiently manage our budget according to our needs and what each printing system can offer us.
All marketing departments should have someone who has experience in this sector. At any given time the company will need to produce printed products. Whether it is to include the logo on cardboard boxes for ecommerce orders, print stickers, develop business cards, produce customized notebooks or we want to attend a fair and exhibition and need to include a variety of material such as magazines, brochures, roll-ups, merchandising items, etc..
In recent years we have experienced a major crisis in the production of printed paper by large publishing groups and the press. The following printing systems have been able to adapt very well to the business demand, an environment where the customer can become more demanding, looking for a more and more personalized work.
The offset printing system has been the most widely used for many years when printing on paper. In recent years, however, digital printing has been gaining ground.
Offset printing is still an indirect printing system. It is called indirect because the image does not go from the plate to the paper directly. Instead, the image goes from the plate to a rubber and from this rubber to the final substrate. The rubber gives a lot of flexibility and thanks to it the ink is able to impregnate on surfaces that may have somewhat irregular textures.
The plate is a flat metal surface with a photosensitive film on one side. These plates are monochromatic so they are only capable of transmitting one color per plate. In order to print correctly in full color it is important that the image is pretreated before transferring it to the plate. The image will be decomposed before transferring it into four colors to follow the CMYK color model (Cyan, Magenta, Yellow and Black).
Each processed part of the image will be printed on a plate. Thanks to the combination of these colors, together with the white of the paper, we can obtain a wide range of color, except for fluorescent or metallic colors. Therefore, in order to print a full color image, we will need one plate for each color of the CMYK model, that is, four plates.
Once we have our four plates, they are mounted inside the printing units of the machine. They are placed on the roller, where one side will be in contact with the dampeners and the other with the inking units. One side receives water, while the other side receives ink.
Due to the lipophilic nature of the plate emulsion and the pre-treatment, the area of the plate that contains the image receives the ink, as opposed to the area that does not. The ink with the shape of the image is therefore transferred to the rubber and immediately from the rubber to the paper.
Advantages of offset printing
- The reproduction of an image is faithful and accurate.
- It always offers a higher quality than digital printing.
- We can use offset printing on all types of paper and sizes, while digital printing is still much more limited in this point.
- When it comes to medium or large print runs, it can be the most economical option.
- Offset printing allows better color control. It allows us to find the exact color.
- It is compatible with other special inks such as metallic or fluorescent inks.
Disadvantages of offset printing
- It does not allow customization, since each unique image must be formed by 4 different plates.
- In order to be economical, the production volume must be high, approximately over 500 units.
Digital printing allows printing directly on paper without any intermediary in the process. No rubber or plates are used. It is therefore a direct printing system. It is currently the most widely used type of printing, together with offset printing.
This printing system revolutionized the graphic arts sector, thanks to its immediacy and high quality. There are many digital printing methods, but the most common is the cartridge or toner injection. It is also one of the most widely used printing systems by individuals and companies for internal use. It is a fast and effective way to make low volume prints with a fairly high quality.
Advantages of digital printing
- Digital printing is usually more economical for short or small print runs. For example, it is very practical when we need to print a low volume, such as 500 units or less.
- It is a much faster and more agile printing system. By transferring the image directly onto the paper, and not needing to produce intermediaries such as plates, digital printing has shorter delivery times than offset printing.
- It facilitates a high degree of personalization. Digital printing gives us a range of customization at the individual level, something we cannot achieve with offset.
- With digital printing, we print only what is necessary, and a new print run can be made at any time.
Disadvantages of digital printing
- Digital printing can only print in CMYK, so we will not be able to include special inks such as fluorescent or metallic inks.
- Although the print quality is very high, especially in the latest generation of digital printers, the quality of offset printing is still somewhat superior.
- Digital printing can produce slight color variations. There are programs for color standardization, but they do not always work perfectly. Always ask for a sample in hand so that you can approve it before you start printing everything.
- We must take into account that when we want to make medium or large print runs, digital printing is not so economical. For this type of production, offset printing will have a lower unit price.
Screen printing, also known as permeographic printing, is a printing technique that consists of transferring ink through a mesh stretched over a frame.
It is a direct printing system. We use a frame with a stretched mesh that allows the ink to pass through the parts that correspond to the image and at the same time prevents the ink from passing through the parts that do not conform to the image. The image is printed on the paper by forcing the ink through the open parts of the mesh, with the help of a squeegee or squeegee.
The applications of screen printing are very varied. We can print on textiles, t-shirts, plastics, wood, rubber, etc. It is also used to print large format posters, stickers, or even print on glass.