How Offset Printing Works

You must have wondered a many times, how these magazines and catalogues have no sign of printing on them where as when you print from your small printer, you can feel the ink, but not in the magazines. You are amazed at the versatile designs and vivid colors the printing has produced and often wonder how it is possible.

All of this is done by Offset Printers. These are huge printing machines which require a large amount of space, electricity and ink to work, hence they economical only for large number of prints such as magazines and catalogues. Here a vivid description of their working and their uses:

  • Offset printing is a commonly used for printing technique where the inked image is transferred or offset from a plate to a rubber blanket, then to the printing surface. The process of printing begins by preparing a pre-copy, which can be paste up and in-house created documents which are assembled on the document and an image is scanned from it. This is created by the client and provider to the printer. The printer creates film negatives and positives of the scanned data file and image of the pre-copy.
  • The printing plate is then created by exposing light to the plate, which is filtered by the film. When light passes through the clear areas of the negative and the positive, it hits the polymer. This polymer hardens because of it, and bounces off the negative’s dark areas, leaving the underlying polymer unhardened. The unhardened layer is washed off and the plate is ready for printing. Then the press works mount the plate on a cylinder.
  • Firstly the cylinder is rolled into a water roller, to make it damp. This dampened plate, is then brought under the influence of inked roller. Thus the plate accepts the inks and is ready for creating the images. Then the inked plate is rubbed on to a rubber cylinder which gets the impression along with the inks from the image plate. This rubber plate is further rolled on to the printing medium, which soaks in the ink and prepares the final image.
  • This image is then passed on to the heat section, where the ink is dried off. Then the necessary works like trimming, cutting the paper are done. The papers are sent to the Bindery, where the necessary works of binding, collecting and separating the printed documents are done. For magazines a machine called stitcher is employed which rolls the paper and binds it in required format to create a sharp and effective magazine. This whole process take under an hours and machines as fast as creating such fully ready 5000 pages an hour have been made.

Every print is the dedicated work of editors, writers and designers, which finally shows off when the product is ready. The small visualized product called magazines goes under so many processes to reach our hands is really marvelous and appreciable.

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