Printing Terms

Anilox Roll


An ink metering roll used in flexographic presses. The anilox roll provides a controlled amount of ink to be applied to the printing plate.




Bounce---Plate Bounce


In flexographic printing there are different pressures applied during printing sleeve rotation due primarily to the printing design. At high speeds, variances in the printed and non-printed areas of the plate when pressed against the central impression drum result in erratic movement or bounce of the cylinder. Bounce can be reduced by incorporating breaker bars into the outside areas of the web. Consideration should be given during the design process to reduce the effects of bounce during production printing.




CMYK


Cyan Blue, Magenta, Yellow, Black – inks used for reproducing process color images.




CMYKOGV


Cyan Blue, Magenta, Yellow, Black, Orange, Green, Violet – inks used for reproducing process color images with a wider color spectrum. (See Expanded Gamut)




Delta E


A color calculation to determine if the printed colors pass or fail the specified color target. An industry standard variation of 2.0 Delta E represents when the human eye will begin to detect color shift. (See X Rite)




Density


Also known as reflection density. The light absorbing property of a substrate or film of ink as measured by a reflectance factor. The higher the density the darker or fuller the color.




Dot Gain


Is an increase in dot size inherent in the transfer of ink to a substrate. It is normally measured as a percentage increase. Flexography, in particular, has significant gain from the design dot size. Gain can cause process colors to be inconsistent and can fill in to cause the finished design to look dirty.




Dots (Re-printed Images)


Are fine microscopic ink dots that make up the printed process (pictorial) image. The dots are normally round in shape.




Extended Gamut / Expanded Gamut


Extended Gamut (EG) is used to minimize spot colors, create more vibrant images, reduce printing costs as there are no changes of anilox rollers, no washing of ink pans, and not a lot of changeover except for plates. This is accomplished by adding two or three inks in addition to CMYK (Cyan, Magenta, Yellow, Black), to extend the color gamut and enable the press to print a wider range of colors. This standard extended gamut ink set is then used to simulate all of the many spot colors contained in the color library. With a wider range of color images look more vibrant.




Impression


A term used to represent one print unit – e.g. bag, wrapper, label or pouch.




Impression, Setting Impression


Refers to the area of the printing plate that transfers the image to the print substrate. Setting Impression is the pressure required to transfer ink from the plate to the film.




Line Print


Printing composed of solid blocks of color with no variation in tone or saturation. A block of a specified color (for example, one chosen from a PMS color book) rather than a process color. It is also known as a spot color.




Photopolymer


Printing plates made of monomers and UV initiators that, when exposed to UV light, experience a chemical reaction to make the monomers join together to become a solid mass of polymers. Overwraps uses a digital plate format by Kodak which eliminates all oxygen during UV exposure to produce full flat top dots with sturdy bases and strong shoulders across the entire tonal range. The result is a printing form that is consistent, repeatable, resistant to changes in impression and wear from substrate or cleaning.




Plate Sleeve


A cylinder that is used to hold the printing plates during the printing process. The sleeve circumference is made to an exact size to match the “cut off” of the individual impression or a multiple of that “cut off”.




Plate Thickness


Is the thickness of the photopolymer printing plates. Plates can vary in thickness based on the type of printing and the preference of the printer. Overwraps has standardized on plates that are 0.0067 inches thick. The thickness variation tolerance across the plate surface is minimal. Typical variation is no more than + - 0.00015 inches. Overwraps has strict requirements for the thickness of the relief area (floor of the plate) after it is processed in the imager during plate making. This prevents printing issues, as well as premature plate wear. (See Printing Plates)We use both solvent and water based ink systems - including extended gamut.




Plate Wear/Life


Refers to the number of impressions that a printing plate can print before it is replaced. Typically the process plates wear more rapidly than the line plates.




Print Register


Refers to the location of each color plate printing in relation to the other colors.




Printing Plates


Used to print the customer’s design. The image areas are raised above the non- image areas on the polymer plate. The ink is transferred from the ink roll which is partially immersed in the ink pan. Then it transfers to the anilox roll (or meter roll) which is an engraved roll which holds a specific amount of ink as it is covered with thousands of small cells that enable it to meter ink to the printing plate in a uniform thickness evenly and quickly. Ink is then metered to the printing plate via a scraper, called a doctor blade. The doctor blade removes excess ink from the anilox roller before inking the printing plate.




Process Print


Printing of pictorial images with CMYK (Cyan, Magenta, Yellow, Black) or a combination of CMYKOGVB. (Cyan, Magenta, Yellow, Black, Orange, Green, Violet, Brown)




Setup Film


Less expensive film purchased and used for the exclusive purpose of press make ready which includes setting impression, register, and correct color matching on the press prior to running production.




Sticky Back


This is the two sided tape used to adhere the printing plates to the printing sleeve. There are several different types of sticky back that are designed to work with different printing plates and achieve optimal printing results.




X-Rite


The Spectrodensitometer used for measuring color, opacity, ink density, and dot gain of printed materials. The X-Rite computer software located in the ink room office, and QA lab has a Pantone color library, as well as a customer specific library of colors saved when an item initially prints. Each time the same item is printed, Overwraps uses that reference standard to match color. Tolerances of up to 2 delta E are monitored during each printed order to assure color consistency within each order and from order to order. (See Delta E)