Glossary

The PRINTING United Alliance Glossary serves as an excellent industry terminology resource. It is the language by which we all communicate. Without it, universal understanding would be impossible.

To keep our constituents well informed about changes to the increasingly complex industry terminology, PRINTING United Alliance has developed this glossary of terms. Definitions are for general reference only. Usage may vary between companies, individuals, or national and country customs. The information presented is as accurate as the authors and editors can ascertain and PRINTING United Alliance assumes no responsibility for the use of information presented herein.
  • Pin registration
    A system of registering two or more sheets very accurately by means of punched holes placed over prespaced pins located outside the design area, results in very accurate alignment of the sheets.
  • Pin scratch
    A pattern or design formed by scratching lines through the raw glaze or decoration with a sharp point.
  • Pincushion distortion
    An image that compressed toward the center with distortion most noticeable at the center of horizonal or vertical edges.
  • Pinhole
    (1) Imperfection in the form of tiny transparent dots that appear in printing screens or in process films after development; (2) Print imperfection caused by a combination of surface tension of ink and low receptivity of the substrate, resulting in very small separations of the ink after printing and before drying; (3) Small hole in a decoration extending through the color to the substrate.
  • Pinout
    A schematic that describes the circuit output requirements for an electronic device.
  • Pique
    A knit fabric with a waffle-like appearance.
  • Pit
    A small depression or defect on the print surface, similar to a dimple.
  • Pitch (fine pitch)
    A solid or semi-solid asphaltic substance used in some inks to add flow or length.
  • Pixel
    (1) The smallest tonal element in a digital imaging or display system; (2) A tiny picture element that contains red, green, and blue information for color rendering on a monitor or scanner.
  • Pixel depth
    The number of bits of tonal range capability assigned to the pixels in an image. (Momochrome 1 bit deep; grayscale 8 bits deep; RGB 24 bits deep; CMYK 32 bits deep).
  • Pixel dropping/skipping
    Sub sampling to reduce the number of pixels in an image by dropping every nth pixel from the scan.
  • Pixel replication
    Creating more pixels than are actually scanned by replicating every nth pixel to create the nth +1 pixel.
  • Pixelization
    Graininess in an image when the pixels are too large.
  • Pixels per inch (ppi)
    A measure of the density of scanned information in an image.
  • PL
    Acceptable acronym for polyolefin liner.
  • Plain weave
    A pattern of weave whereby the warp and filling thread (weft) cross alternatively over one and under one. (Plain weave mesh is the least pliable but most stable).
  • Planimeter
    A device that uses a microscope, television camera and receiver, and a small computer to visually and mathematically evaluate a dot area.
  • Planishing
    Method whereby heat and pressure are applied to a film, resulting in a surface texture.
  • Planography
    A printing process where the image and non-image areas lie in the same plane of the plate, such as offset printing.
  • Plasma display
    A display screen that has a gas contained between two panels where the x and y axis dots are electrically charged causing them to glow.
  • Plasma treatment
    An electrically neutral highly ionized gas made of ions, electrons, and neutral particles used to treat polyolefin plastic prior to printing.
  • Plastic
    (1) A synthetic organic polymeric material, solid in its final form, that is either a homogenous polymer or resin combined with fillers, plasticizers, pigments, stabilizers and/or other additives; (2) Any of various complex organic compounds produced by polymerization, capable of being molded, extruded, or cast into various shapes and films, or drawn into filaments for fabrics.
  • Plastic deformation
    A forced change in the dimensions of an object that does not return to the original, when the applied force is removed.
  • Plastic fluids
    Fluids where flow does not occur until a critical shear stress (yield stress) is exceeded.
  • Plasticity
    The property of a material that allows it to be repeatedly deformed without rupture, when acted upon by a force sufficient to cause deformation, and allows it to retain its shape after the applied force has been removed.