Offset Printing Technology – How does it work

Offset Printing technology is renowned for its consistent and impeccable high quality printing that gives it an edge over other printing technologies; making it the most renowned printing technology.

Color Wheel

We use plates to print on flat services in this process. There is a plate that has been chemically treated only to accept ink at certain areas like image areas (for example type, colors, shapes and other colorful elements). Then we apply water and ink onto the plate, just because of the chemical treatment done in last step the water does not stick to that place which is ink acceptor like the image areas. Those areas without images accept the water. The purpose of those special multi-layer rubber printing blankets is to transfer the illustrations or images to the sheet and this keeps itself repeating every time a cardboard goes through the printing machine. When we are printing a full color job then the cardboard is overprinted round 4 times over four different printing units while using separate colors.

Offset Printing ‘CMYK’ rollers

The colored offset printing uses four colors to generate all the colors which are known as CMYK

  • C stands for Cyan (Quite like blue and green mixed together)
  • M stands for Magenta ( Somewhere in between red and blue spectrum)
  • Y stands for Yellow and
  • K stands for Key ( the black key plate)

Some of the terms associated with this type of printing are

  • Aqueous Coating –Water based coating for the protection and intensification of the impression
  • Impression Cylinder –this is a cylinder whose purpose is to press the cardboard sheet against the Blanket cylinder while ensuring the transfer of colors onto printed surface of cardboard. It rotates in opposite orientation than blanket cylinder so that the cardboard transports well in between them.
  • Color Management System (CMS) –is computer software made to vet the uniformity of quality throughout the printing run by maintaining the complete coordination of scanners, monitors, printers and printing machines.
  • Chromo Paper –This is a paper which has two coatings one with wood pulp or rag paper and the other one is water resistant coating.
  • Ink Volume –is the amount of ink used for printing surface. This volume is highly important for achieving the required impressions and designs, and also depends on raster.
  • Fountain Solution –is used to wet the offset printing plates that in turn prevents the color from being accepted on areas without ink. Overall it is a mixture of ink and other chemicals.
  • Raster –are lines arranged parallel to each other defining the number of lines per vertical in centimeters, slope of lines slanted by the generating roller. Raster graphics are just a set of samples of a given space which are generated digitally of any given space. A raster is just a grid of X and Y coordinates on a display space. A raster image files has all the information regarding these coordinates where it is needed to illuminate in monochrome or color values.
  • Duplex Board –is multilayered paperboard that has a gray intermediate layer, and a gray back with wood free coat on one side.
  • UV inks –these are those inks which gets polymerized as color after UV rays strike against the drop of UV ink that was transported before, causing the ink to harden. These colors have some special chemicals, few photo initiators that accelerate the polymerization making the ink to go dry as soon as the UV light strikes it.

Why we consider offset printing an advance technology in comparison to other printing technologies?

  • Everlasting Excellent Quality End Result –many technologies have undefined stages of quality and non-uniform but that is not the case with Offset. Just because the fine rubber layer sticks to the printing surface perfectly, the image quality of illustrations is guaranteed for every print job.
  • Fast and Simple –the construction of printing plates is super fast
  • Durability of Printing Plates –usually the offset printing plates have a long life that is it is durable for a long time. This durability is because the printing surface and printing plate do not touch each other.
  • Investment –Offset printing is famous for being the most economic technique for excellent quality printed products in large quantities.

What are the drawbacks of Offset Printing in comparison to other printing techniques?

  • Time Period Limitations –it renders useless when you need an urgent printing job done. No instant print job is done. In this case Digital Printing takes the lead offering better immediate solutions.
  • Sensitivity of the plates –the aluminum plates are reactive to certain chemicals making them fragile.
  • Rotogravure Printing offers and even better quality than Offset Printing.

Leave a Comment

Your email address will not be published.