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.
  • Photostencil
    Any light sensitive system that utilizes original or photo-generated artwork to produce a stencil.
  • Phototype
    Type set by photographic means.
  • Phototypesetting
    Act of preparing type material by photographic means to provide a positive film with the type matter in predetermined arrangement to form a line or lines.
  • Phthalocyanine blue (cyan)
    Blue green organic pigment used in process color printing ink, characterized by excellent light fastness and resistance to solvent, acid, and alkali, resistant to bleed, good transparency.
  • Phthalocyanine green
    Green organic pigment with excellent lightfastness and resistant to acid and alkali, bleed resistant, good transparency.
  • Pi
    (1) A mathematical symbol representing the ratio of the circumference of a circle to the diameter, the numerical value of which is 3.14159265+ or 3.14; (2) Foundry type mixed and jumbled in an unusable condition.
  • PIA
    Acceptable acronym for Printing Industries of America.
  • Pica (p)
    Printer’s unit of linear measurement used for measuring type lines and artwork; equal to 12 points or 1/6 of an inch.
  • Pick
    Paper fiber or coating lifting from the surface of a sheet during the printing process.
  • Pickup
    The adhesion of ink from the first color printed to the underside of the screen for the second or succeeding color.
  • Pico (P)
    A prefix utilized in the metric system of measurement that denotes 10 to the negative twelfth power (10-12) or 0.000 000 000 001.
  • Pictograph
    A pictorial representation used with or instead of text.
  • Piezo-electric
    Ink jet technology that uses a mechanical electric charge instead of heat to drive micro-droplets through a nozzle.
  • Pigment
    (1) A substance used as a colorant; a finely divided solid, organic or inorganic coloring material insoluble in the medium into which it is added; (2) The color substance in an ink that absorbs and reflects light.
  • Pigment dye
    Textile dye formulated from appropriate vehicles and pigments of mineral or synthetic origin.
  • Pigment emulsion
    Emulsion type screen printing ink that contains pigments for coloring effects mixed with emulsified vehicle.
  • Pigment volume
    The percentage by volume of a pigment in the nonvolatile portion of an ink, calculated from bulking value and other data.
  • Pile feeder
    An automatic sheet feeding mechanism.
  • Piling
    The tendency of a textile fabric to mat into ball-like "pills" that cling to the surface of the fabric.
  • Pill
    A tangled ball of fibers that appears on the surface of a fabric.
  • Pimple
    Any small defect such as a protrusion on the surface of a plastic.
  • 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.