Glossary Of Terms

The SGIA 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. SGIA 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 SGIA assumes no responsibility for the use of information presented herein.


  • Electroluminescence (EL)
    The direct conversion of electrical energy into light by solid phosphor subjected to an alternating electrical field.
  • Electrolyte
    (1) A non-metallic substance, when in solution or fused, is capable of conducting electric current; (2) Chemicals (soda and silicate of soda) used to make slip more fluid for casting.
  • Electromagnetic spectrum
    The complete range of wavelengths and frequencies of electromagnetic radiation extending from gamma rays to the longest radio waves including visible light.
  • Electron beam
    A continuous stream of electrons used to cure or crosslink reactive inks and coatings.
  • Electronic dot generation (EDG)
    Process used in digital halftone production that allows negatives or plates to be generated by grouping micro dots into regular groups to function in the same manner as a photographically produced halftone.
  • Electroplating
    A process of depositing metal particles onto a conductive surface by electrolytic action.
  • Electroscopic ink
    Finely ground, spherically shaped, dry particles of resin and coloring matter that take a static charge from the metal screen and are thus attracted through the openings in the stencil that forms the design to the grounded back plate.
  • Electrostatic decorating
    A method of decorating an article utilizing the phenomenon of opposite electrically-charged particles attracting each other such as flock or ink particles applied to a substrate by positively charging the particles and negatively charging the substrate.
  • Electrostatic film
    A PVC plastic sheet that has been electrostatically charged so that it "clings" to any highly polished surface without adhesive, offering easy removal and reuse capability.
  • Electrostatic flocking
    A process using an electrostatic charge to drive flock fibers into an adhesive that has been printed on a substrate.
  • Electrostatic printing
    An impact-less imaging process where electrically charged, powdered colorant particles are transferred from the image carrier to a substrate and fused to the substrate to form a permanent image.
  • Elliptical dot (chain dot)
    An elongated oval shaped halftone dot that forms an image that tends to produce better tonal gradations across 50% tint area; also called a chain dot.
  • Elliptical reflector
    A direct light source reflector used in UV curing for focusing the energy onto a specific area.
  • Elmendorf test
    A standard test for determining the tear strength of a material such as paper.
  • Elongation
    (1) Loss of memory or irreversible change in the dimensions of a screen mesh that has been over-stressed; (2) The increase in length or width of a material produced by extending it to the point of rupture; (3) Length of printed image stretched or increased in size; (4) The difference between the length of a mesh thread before and after tensioning.
  • Em space (em quad) (mutton) (mutt)
    Defined as a square equal in width and height to the height of the letter "m" in any size type, and used as a unit of measure for printing matter.
  • Embedment
    A process where pre-screen printed graphics are placed within a translucent polyester resin containing fiberglass strands, to produce a durable outdoor sign or other item. (The graphics are printed onto rice paper or special embedment papers with cellulose inks).
  • Emboss
    Mechanical and thermoforming of graphic features, providing a raised area for accenting key surfaces, logo, and to allow for embedding of surface mount LED within the switch.
  • Embossed pillow
    A raised surface in the graphic overlay over the entire key area (0.10 to 0.015 high).
  • Embossed rail (embossed racetrack)
    A raised ridge around the perimeter of the key area (0.10 to 0.015 high).
  • Embossing
    A technique for impressing a design or texture into a sheet of material from the back of the sheet so that the design, though remaining an integral part of the sheet, extends forward toward the viewer.
  • Embossing die
    A brass, steel, or magnesium die used to impress a design in relief.
  • Embrittlement
    The loss of plasticity in a material resulting in brittleness.
  • Embroidery
    The process of working with needle and thread to form raised decorative designs on fabric.
  • EMI
    Acceptable acronym for electromagnetic interference.