|           ABOUT          PRINTING
 Printing in          its broadest sense, is any process whereby one or more copies are produced          from master image.Image transfer from master to copy is usually accomplished          with inks and the transferring agent is a mechanical press.Most          commercial printing is achieved through one of the following process.          They are Relief printing, Offset Lithography and Gravure printing. PRINTING          PROCESS AND TYPE Tthe          printed communications begins with a plan that is followed by or jointly          prepared with the words and illustrations needed to accomplish the goals          of the communications.•Due to the invasion of digital media (offset printing) made the          production
 •Even more preparing printed media using computers.
 •We have many process, but the best is Photo offset Lithography          or offset process. This uses metal images to carry ink to paper from a          flat surface.
 •Offset          printers work with the basic principle that water won’t mix up with          oil. The printing plate holds ink because the image area is treated so          that it is receptive to oil based ink not to water.
 •A multi-color offset press has a separate printing unit for each          ink being printed.
 •The          steps involved are:-Plate making.
 Wetting.
 Inking.
 Offsetting.
 Printing.
 •Wetting is a process in which the plate is mounted on a rotating          cylinder. When the press starts, the plate comes into contact with the          water rollers first.
 •Dampening solution flows constantly from a tray like fountain through          series of rollers wets the entire printing plate, except where the plate          has been treated to resists water.
 •Plate          making is a process whereby a printer exposes the reversed image from          a film separation (negative) onto a flat plate with light-sensitive coating,          and then develops the plate.
 •The image area of the plate — now a readable positive is          coated with a chemical that attracts ink but repels with water.
 •Offsetting          is where the final roller, which is a rubber blanket, will be pressed          against the printing plate and carries away a reversed inked image.
 •The rubber blanket has some flexibility and gives slightly when          pressed against paper, so the image can transfer evenly to both smooth          and textured paper.
 •Printing          -In the last step, the paper in individual sheets or on a continuous roll          passes between the rubber blanket and an impression cylinder.
 •The inked blanket cylinder with its reversed image presses against          the paper, printing the +ve image.
 CALIBRATING YOUR SYSTEM
 The first          step in Color separation is calibrating Our devices (monitor, printer,          scanner) and have Correct system-wide color calibration. Calibration          is of two types viz, device calibration And system calibration. Device          calibration works with monitor and making adjustments for the image setter          that we’ll use when we do color separation. System calibration          is adjusting the Adobe Photoshop settings that affect the image when it          has been converted from RGB to CMYK. Calibrating          an image won’t affect it in RGB, because monitors are RGB devices.          Changes are only for CMYK. Don’t set changes in CMYK, always comes          to RGB and then change the mode. Producing          a best scan. Although Photoshop          corrects scanned images, it cannot correct images which doesn’t          have much color details init — either because it was scanned at          a too low resolution or because it lacks detailIn the highlight and shadow areas.
 To make good          second originals, do the following steps properly: StepsDetermine the exact scan resolution for according to your requirements.
 Take care          of size of the image according to the scan resolution. Scan always          by using the file size settings. Eliminate          the unwanted color casts by calibrating Your monitor. Separation          setup adjustments. The settings          in the Separation Setup dialog box along with the settings in Printing          Inks dialog box control how CMYK plates are Generated. The Separation          settings include the method used for Black generation, under color removal          and total ink limit for the press. When Adobe          Photoshop converts an RGB image in to CMKY mode, the program converts          the values Using information in the Monitor setup, Printing ink setup          and Separation setup dialog boxes. The first          two settings will provides a closest match for the onscreen and final          output image. The separation Setting will give the precise CMYK value          chosen for a given RGB color. Color separation          is based on the principle of translating the three additive colors —          red, green and blue — into their subtractive colors- Cyan, Magenta          and Yellow. Theoretically, equalParts of cyan, magenta, yellow combine to Subtract all light and create          black. Due to certain impurities present in all printing inks, however          a mix of these colors instead yields a muddy brown.
 To compensate          to this deficiency, we add black ink to the final image output. There are          many ways that a given color can be translated from RGB mode to CMYK mode.          Pre-Press operators typically use one of two styles of color translation.          They are 1.Under Color          Removal (UCR)2.Gray Component Replacement (GCR)
 For both UCR          and GCR, the black generation uses the ink settings we enter in the Separation          Setup Dialog box. (Black ink limit is 100 and total inkLimit is 1000.)
  
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