By Steffen Andersen · 12. May 2020
Offset printing is one of the most used printing methods and especially when it comes to printing paper articles such as magazines, newspapers, and paper cups. The reason why it is so commonly used is that it is really efficient and can print a high volume in a very short amount of time. So in this article, we are going to dig into how it works, what it is primarily used for, and compare it to some of the other printing methods.
Offset printing is also known as offset lithography. The process is actually rather simple: it works by making printing plates that contain the image or graphics that you want to be printed. The printing plates are made by aluminum, and they are put into offset printing machines. The reason why it is referring to offset is due to the fact that the printing plates are not transferring the graphics directly onto what you want to have printed. The ink is transferred from the printing plate to a rubber blanket and then to the printing surface.
To make sure that is only the graphic area of the printing plates that are printed, the offset printing machines have a dampening system that moistures the non-graphic area, so it does not repel the ink. Depending on how many units need to be printed, other adjectives can be added to make sure the ink of the non-graphic areas is not repelled.
The ink is added to the printed files one by one because the ink is added to the print through the printing units. The standard for offset printing machines is to have four printing units because it can then using the colour scheme CMYK, and each colour is then added in one unit at a time. But the Pantone colour scheme can though also be used for the offset printing method, the more printing units the process have the more Pantone colours can be added in the print.
In the offset printing machines, it is cylinders that make it all come together. The first cylinder and most important one is in the top of the machines and holds the printing plates, next to this one there is the cylinder holding rubber blanket which transfers the ink onto the object. It is these cylinders that make the object go from one printing unit to another printing so the object can be printed in different colours.
When the object has been printed it will shortly be heated and then cooled off to make sure that print is clear and they can be stacked.
As the offset printing process is easily adjustable in terms of colour schemes and what the rubber blanket can print on, it can be used for almost all purposes. We work with a lot of manufacturers who use the offset printing method for both paper cups, plastic cups, and ice cream cups. As I said, in the beginning, it is though most commonly used for printing newspapers and magazines.
Offset printing and flexographic printing are very familiar and have many of the same benefits: Great at larger quantities, can both use Pantone and CMYK colours (but offset normally uses CMYK colours), and the quality of the print will come in high resolution and they are both often used for printing on packaging.
The two main difference is that; flexo print is easier to adapt to print on other surfaces than paper and more convex surfaces. The other one is that offset print has lower start-up cost since the printing plates are easier to make and it can therefore ofter also be used for printing in lower quantities. If you want to know more about flexography, then check out our article about it.
Offset printing and digital printing are the most used printing methods for paper products. Since digital printing does not use any printing plates, the printing method is great for small quantities and make test prints, where offset printing is a more efficient printing method and is used for larger quantities. Digital printing cannot be used for printing on other materials than paper, since the colours are mixed by dropping ink on the object all the time, and only CMYK colours can be used. Offset printing is a bit more adaptive and can be used for other objects and both CMYK and Pantone colours can be used in the printing process. Need more information about digital printing – find it here.
Tampon print and offset print has a lot of differences and they are often used for different purposes. Both of the printing methods are though used for printing on food packaging. Tampon printing is great for printing on complex surfaces in smaller quantities because the printing process is rather manual and the print is added directly from the printing plates. Where the set-up and start-up for offset printing is a lot longer, and since offset printing is automated a lot more, the process is not great for printing on convex surfaces. But offset printing can both use CMYK colours and Pantone colours whereas Tampon can only use Pantone colours. Do you want to know more about Tampon print? Then check out this article.
Rotogravure printing is properly the least known printing method, but it is still used by some printing companies who print very high quantities for more luxurious paper products. The start-up cost for rotogravure printing is very high because the printing plates are made as a cylinder. So for it to be cost-effective it will normally have to print many millions of the same print before it is more effective than offset printing. The printing method is though very similar to offset printing, where they can use CMYK and Pantone colours and primarily used for paper products. Do you want to know more about Rotogravure printing?
Letterpress and offset print are actually a rather funny combination because offset printing is the most used printing method where letterpress is properly the least used printing method. They are though both primarily used for printing on paper. Both printing methods can use CMYK and Pantone colours, but letterpress does primarily use Pantone were offset primarily uses CMYK colours. Offset printing is great for printing high volumes and large quantities, where letterpress is used for more special projects. Due to offset being a newer printing technique the print is also in a lot higher quality. Read our article about letterpress printing.