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.


  • Laser
    A high energy single wavelength pin-point light.
  • Laser scanner
    A device that uses color filters and beams of light to produce tone and color corrected separations for process printing.
  • Latent charge
    Electrostatic printing, the charge remaining in the area not exposed to light and dissipated.
  • Latent curing
    The use of a curing agent that is stable at room temperatures, but promotes a rapid cure at higher temperatures.
  • Latent image
    Invisible image on exposed film that has not been developed.
  • Lateral reversal
    Left to right or mirror image reversal.
  • Layflat adhesive
    An adhesive having the property of resistance to warping in laminations.
  • Layout
    (1) A guide showing the arrangement and location of all type, illustrations, line art drawings, or sketches of a proposed printed piece; (2) The floor plan view of a printing plant or manufacturing area.
  • Lays
    The fixed guides used to register a substrate on the printing bed.
  • Laysides
    The two sides of a sheet set against register guides (lays) for registration during screen printing.
  • Lazy flame
    A type of flame resulting from a gas rich mixture.
  • Lc
    Acceptable abbreviation for lowercase.
  • LD
    Acceptable acronym for laser diode; abbreviation for lethal dose.
  • Leachate
    Liquid, including any suspended components in a liquid, that has percolated through or drained from hazardous waste.
  • Lead dryers
    Chemical combinations of lead with various organic acids that are used to accelerate the drying of screen printed ink film.
  • Lead glass
    Glass containing a substantial portion of lead oxide (PbO).
  • Lead-free ink
    Inks and coatings formulated for special purposes that contain less than 0.06% lead by weight measurement (US).
  • Leading edge squeegee
    The corner of the squeegee blade that contacts the mesh during the printing stroke.
  • Leafing
    A phenomenon where metallic pigments form a layer parallel to the surface of the substrate, yielding a high metallic luster.
  • Lean
    A color and oil mixture, that does not flow easily and smoothly on application.
  • Lean mixture
    A type of flame resulting from an air/gas mixture where too much air is present.
  • Least-square lines
    In statistical computations, the straight line for which the sum of the squares of the residuals (deviations) is minimized.
  • Leather hard
    Clay that is dry enough to hold its shape, but damp enough to work with tools.
  • Ledger paper
    A durable grade of business papers generally used for record keeping.
  • Legend
    Characters, nomenclature, text, type and/or symbols to be printed.