Nowadays the most popular printing methods for commercial material –brochures, posters, post cards, labels, catalogues, personal cards, etc. - are offset printing and digital printing. This section of our website will deal with them simply and briefly.
This widespread printing method has the characteristic of being a system based on metal plates, rubber, oil inks, water, and hydrophobic compounds. Prior to the printing itself, the design is transferred to different plates. Using a special transfer system, the chosen design is transferred from a file first to a film, then to a coating that is later transferred to an aluminum plate. This plate is then moistened with water and oil inks in order to transfer the design to a rubber blanket. This rubber blanket is placed in a roller and when it comes into contact with paper it produces prints. Each color of a design needs a different film, coating, and aluminum and rubber plate.
Basically, offset printing works with oil inks, water and chemicals that repulse water. Those parts of the design that want to be printed are covered with these chemicals. Then the plate is wetted with water and ink in a way that ink remains in those sectors that will be printed first in rubber and then in paper. This printing system -also known as lithographic process- owns its popularity to the fact that it can be used in all types of paper, it has a very good image resolution, and it can be used with two different methods: Chromatic CMYK -cyan, magenta, yellow and black, which are mixed to obtain different colors- and Pantone. It is ideal for the printing of high and medium quantity runs, since it is important to make good use of each plate production. This system is also famous because it is used to print in all types of surfaces: paper, wood, cloth and metal.
It is important to add that offset printers work with paper rolls or paper folds –paper cut beforehand. Printing firms working with paper rolls are big in size and thanks to their machinery and rolls it is possible for them to print high quantity one and two-sided runs. Within offset printing there are drying systems that produce good prints that are printed in a short period of time and in papers with finish –such as text paper. In other cases ink is left to dry without the use of this system, as is the case of runs printed in paper without finish–which quickly absorbs ink. The quality of images is inferior to those produced with drying systems, but they cost less money. Printers using folds display the characteristic of having good image definition. In general they produce low quantity runs, since this type of printing is costly because of its production timeframe.
Although this method is also offset, it is significantly different from offset printing, since digital printing does not require the use of plates. Today, it is the system most commonly used due to the cost advantages for low quantity runs. This printing technique is inexpensive because it does use plates, which means that designs go directly from computer to the printing surface and therefore a lot of time and money is saved. Like conventional offset printing, this method is used to print in different types of paper, in all colors and producing designs of very high visual quality. Some of the advantages of digital printing are:
It is a low-cost printing technique because it does not use plates.
It is possible to print low quantity runs– no more than 100 copies -, while in traditional offset printing it is convenient to print high volume jobs in order to make profit of the cost of plates.
You can correct the design before printing because it is possible to visualize the digital files, while in traditional offset printing making corrections involves having to remake the metal plates.
It is possible to customize each print because, as we asserted above, each print is digitally arranged. That way, it is possible to obtain customized personal cards, posters, catalogues, personal cards, etc.
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