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.


  • Reflective sheeting
    Sheet material with one face treated with a substance, usually microscopic glass spheres that return light rays striking it.
  • Reflectivity
    The capacity of a surface to reflect light rays.
  • Reflex blue (alkali blue)
    A strong organic blue pigment with the highest tinctorial strength of any blue pigment.
  • Reflex copy
    The exposure of a photosensitive film by passing light through the back of the film, then through a positive or negative, and reflecting the light back from the support surface.
  • Reflex paper
    A light sensitive material for contacting same size reproductions.
  • Refractive index
    The deviation of light as it passes through a given substance, given as the ratio of its velocity in a vacuum to its velocity within the substance.
  • Refractometer
    An instrument for measuring indices of refraction.
  • Refractory
    A material that has a relatively high melting temperature and is capable of enduring continuous high temperature.
  • Register (in register)
    (1) To precisely align either manually or automatically one print color to another; (2) A mark on a design that identifies it as having been officially recorded with the US Patent Office.
  • Register bond
    A common lightweight writing paper designed for single- and multi-copy business forms.
  • Register check
    A mylar roll material that is coated with a light adhesive used to determine registration without printing a actual production sheet or part.
  • Register device
    A mechanical device used to align a design elements prior to or during printing.
  • Register guide (feed guides, three-point lay)
    Physical stops, usually three in number, placed on the printing base in relation to two adjacent edges of the printing sheet to ensure proper positioning for printing; also called feed guides.
  • Register guides
    Stops on the printing base against which edges of substrate are placed for printing to ensure that all substrates are being printed in identical areas or positions.
  • Register locking system
    A mechanical system where a printing screen and its printing base can be locked into position after adjustment to accomplish register.
  • Register mark
    A crosshair or other target image applied to original copy as an aid for positioning and aligning purposes.
  • Register punch
    A device used to cut holes in film flats to ensure registration.
  • Registered numbers
    Heat-applied numbers that are centered on a transfer sheet of paper with precision.
  • Registrar
    A company that conducts quality system assessments to recognized quality system standards or set of requirements.
  • Registration pin
    A spring loaded finger inside a chuck that locates the ramp or lug and stops rotation at the registration point.
  • Regression analysis
    Models the relationship between one or more independent variables and a dependent variable.
  • Regrind
    Excess or waste material in a thermoplastic molding process that can be reground and mixed with virgin raw material.
  • Reheology modifier
    Alters the flow characteristics of an ink.
  • Relative humidity (RH)
    The amount of water vapor present in the atmosphere expressed as a percentage of the maximum that could be present at the same temperature.
  • Relative mesh strength
    A calculation of a specific cross section area of the threads.