For small print runs, it is more economical to use digital press. On the other hand, offset printing is more cost effective for larger runs, for example newspapers. Besides rotating offset, there is offset printing too. Let us have a look at how the latter one works and when it is a suitable option for you printing.

Posters, flyers, magazines and business cards

Offset printing is mostly used for printing posters, flyers, magazines, brochures, newspapers, books, calendars, business cards or headed papers. Offset printing does not use a rotating paper roll. It is a printing method in which individual sheets of paper are fed into the machine. There are two types of offset sheet printing method: wet and dry.

Wet offset printing

This printing method uses varied materials of a print form. One of them is hydrophobic, which tends to repel water, the other one is hydrophilic, which absorbs water. The parts of the plate which need to be printed are hydrophobic, whereas the unprinted parts are hydrophilic. The inked areas with the image are transferred to the paper. The most important advantages of wet offset printing include a high-quality image and delicate details. However, the reproduction of the colour may be difficult. When printing at least five hundred copies, it is worth considering wet offset printing method, as the expenses on starting the machine are high.

Dry offset printing – cheaper and faster alternative

Dry offset does not need any water and uses two material layers. The bottom polymer layer, which absorbs the ink is covered with a layer of silicon which repels the ink. In the printing machine, the silicon layer vanishes from the printing areas. The surface absorbs the ink and is ready for printing. The print preparation is much simpler and faster compared to the wet offset because the entire process is in the machine. The first printing output can be ready within 10 minutes from putting the data into the machine.

With dry offset you get a high-quality output. High gloss, better stability of the ink, and finer raster. The main disadvantage of dry offset is colour peeling off the boundary line between the printed and non-printed areas. Small white stains appear. However, the problem, which occurs after hundreds of outputs have been printed can be eliminated by washing the cylinders.

From the economical point of view, dry offset is recommended when printing at least a hundred copies, but no more than 20,000 to 30,000 copies. After having printed more than the recommended number, printing plates must be changed, and it makes the commission more expensive.

UV offset dries immediately

UV offset print uses special printing inks containing photo indicators. These are sensitive to UV light and that is why they harden and dry immediately. The advantages are bright colours, gloss, high resistance of ink to scratch or abrasion.

Conclusion:

  • Offset sheet printing uses sheets of paper compared to rotating offset where a roll of paper is used.
  • The traditional wet offset is recommended for more than five hundred outputs. Printing process preparation is longer and more expensive.
  • Dry offset is convenient for printing a smaller volume of copies (a hundred). The printing process preparation is quick, and the first copy is ready within 10 minutes.
  • Due to the absence of water, it is easy to keep the colour balance. On the other hand, the ink may peel off and white areas appear on the copy.
  • With UV print, the colours dry quickly, which makes the printing process faster.