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.


  • Overglaze enamel
    Screen printing ink applied to ceramic or glassware as a finish to impart high gloss or color change.
  • Overlaminate
    A protective clear film that extends an image's outdoor life and enhances its visual quality.
  • Overlap
    To make shapes to lap one color over another to ensure that subsequently printed colors will appear in register.
  • Overlap lock
    A display lock for constructions that require placement of lock within the display rather than at its edge.
  • Overlay (transparent flap)
    Top layer graphical interface of a membrane switch.
  • Overlay of colors
    The printing of a color on top of a preceding color.
  • Overprint varnish
    A clear, screen printable compound printed as a protective coating over a design.
  • Overprinting
    Copy or graphic printed directly over an area that already has been printed.
  • Overrun
    Copies of printed material that exceed the number ordered by the customer.
  • Oversampling
    Scanning at more than an optimum sampling rate. See also subsampling.
  • Overshoot
    The number of degrees that a process involving heat exceeds the set-point when raising to the set point temperature.
  • Oversize
    Substrate made larger to allow for trimming to ordered size.
  • Over-travel
    The additional movement of a rubber key pad or metal dome after making contact with the circuit.
  • Oxidation
    The effect produced by contact with oxygen, either in the atmosphere or introduced in more concentrated form, such as drying in some screen printing inks or deterioration of photographic developers in open trays.
  • Oxide colors
    Inorganic or mineral base pigments used in porcelain and vitreous glass enamel colors.
  • Oxidize
    To combine with oxygen.
  • Oxidizer
    A chemical that initiates or promotes combustion in other materials, thereby without the aid of an external ignition source causing fire either of itself or through the release of gases.
  • Oxidizing agent
    Material that causes oxidation of an atom or ion and is reduced in the process; (oxygen is a common oxidizing agent).
  • Oxidizing atmosphere
    (1) Sufficient oxygen content in a lehr to produce or support combustion; (2) Air volume containing oxygen sufficient to promote drying of wet ink applications by oxidation; (3) An environment with an oversupply of oxygen.
  • Oxidizing ink
    Screen printing ink that changes from wet to dry state on contact with atmospheric oxygen.
  • Oxy
    Oxidizer, any substance used to unite with oxygen, or which causes another to oxidize.
  • Oxygen inhibition
    The effect of oxygen to terminate or slow a polymerization reaction by deactivating radicals.
  • Ozalid
    A trade name describing a method of copying page proofs from paper or film.
  • Ozone
    Gaseous form of oxygen (O3) containing three atoms to the molecule generated by electric spark or a high-voltage discharge across a stream of air, causing oxidation of metals and other materials.