Glossary Of Terms

The PRINTING United Alliance Glossary of Terms serves as an excellent industry terminology resource. It is the language by which we all communicate, without it universal understanding would be impossible. Language and our ideas about how it is interpreted change rapidly. PRINTING United Alliance is aware of this and continues its effort to keep our constituents well informed about changes to the increasingly complex industry terminology. The 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.


  • Lossless compression
    A compression technique that will retain all of the file's original image characteristics. The perfect lossless compression technique remains elusive.
  • Lossy compression
    A compression technique that will sacrifice some image quality at low levels and continue to degrade more image quality as compression levels increase.
  • Lot number
    A control number assigned to a material by the manufacturer to track specifics on when and how it was made.
  • Low carbon hot oil
    Thermoplastic vehicles that burn out easily.
  • Low elongation mesh
    Screen mesh made from a specially formulated polyester known as LE that has greater stability and can be stretched to higher tensions.
  • Low key
    A photograph or other image whose tonal range is mostly in the shadow regions.
  • Low tack adhesive
    An adhesive with an initial non-aggressive character for ease of application that usually becomes a more permanent bond after 24 hours or other pre-selected time period.
  • Low-density polyethylene (LDPE)
    A thermoplastic made from the monomer ethylene and defined by a density range of 0.910–0.940 g/cm3.
  • Low-energy dyes
    Dyes that require relatively low transfer temperatures (usually under 191ûC or 375û F) to effect sublimation.
  • Lower capability performance (CPL)
    A measure of the relationship between the performance of a process and the lower specification limit.
  • Lower case
    Uncapitalized letters of the alphabet.
  • Lower exposure limit (LEL)
    The lowest concentration of gas or vapor (% by volume in air which will burn or explode if an ignition source is present.
  • LSE
    Acceptable acronym for low surface energy.
  • Lumen
    A unit of measure for the flow of light.
  • Luminescence
    A phenomena of light emission by a chemical composition which is film-forming and which absorbs light, releasing it when extraneous light sources have been removed; a "glow-in-the-dark" capability.
  • Luminous reflectivity
    When specifying a color, it is the ratio of the luminosity of the specimen to that of a standard reflector under identical conditions.
  • Luster
    A solution of organic pigments modified with suitable oils, resins, and solvents that are fired to produce an iridescent surface appearance on the ware.
  • LUTS
    Look-Up Tables: A digital processing method to modify data from the input to the output, by using an array of data from a stored table.
  • Lux
    (1) A metric unit of illumination; (2) The amount of illumination produced by a light source of one candela intensity on a surface one meter or 3.28 ft distant (lux x 0.00929 equals foot candle); a unit used to define the illumination falling on a surface.
  • Lux second
    Unit of exposure expressed in the metric system for illumination; equivalent to that produced by the illumination intensity of 1 candela at a distance of 1 meter for 1 second. (English equivalent is footcandle/second).
  • Luxometer
    Photoelectric device used to control the duration of camera exposure according to actinic light and fluctuation of camera lamps.
  • LZW
    The Lempel-Ziv-Welch image compression technique.