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.


  • Recycle
    To restore waste or spent material to a reusable condition.
  • Red (R)
    One of the three additive primary colors of light.
  • Red 28
    An organic pigment with fair transparency, good bleed resistance, fair to good lightfastness, and poor resistance to acid and alkali.
  • Red iron oxide
    An inorganic pigment with excellent fade resistance, good hiding ability, good resistance to acid and alkali, resists bleeding, poor gloss.
  • Red label
    The color and type of label required by the Department of Transportation (DOT) on shipment of flammable materials (US).
  • Red lake C
    A warm, bright red pigment used in printing inks.
  • Red lead
    An orange red oxide of lead similar to orange mineral, formally used in printing ink.
  • Reducer
    A solvent or other additive used for lowering the viscosity and tack of an ink formulation.
  • Reducing atmosphere
    A furnace environment that tends to remove oxygen from a substance or material placed in a lehr or kiln.
  • Reducing flame (rich flame)
    A rich flame or fire resulting from a mixture containing too much fuel or too little air for proper combustion.
  • Reduction
    (1) The amount of, or the act of, thinning an ink with a compatible solvent; (2) A decreased size or area of an original copy, made photographically in a camera, or manually by pantograph, or dividers.
  • Reference colors
    Familiar colors, such as blue sky, green grass, and human skin tone, often referred to when evaluating process color reproduction.
  • Reference edge
    The area on a data medium used to establish specifications or measurements in or on the data carrier.
  • Reference state
    The position of a fabric in relaxed condition after five washings.
  • Reflectance
    The ratio between the amount of light reflected from a given tone area and the amount of light reflected from a white area.
  • Reflectance (specular)
    Mirror-like reflectance. The magnitude of the specular reflectance on glossy materials depends on the angle and on the scattering of the light by an uneven surface.
  • Reflectance (total)
    Reflectance of radiant flux reflected at all angles from the surface, thus including both diffuse reflectance and specular reflectance.
  • Reflection
    The direction change of a ray of light when it falls on a surface and is thrown back into the medium from which it approached.
  • Reflection (diffused)
    Parallel incident rays that are reflected at various angles from a rough surface.
  • Reflection (specular)
    Parallel incident rays that are reflected at a constant angle from a smooth surface.
  • Reflection densitometer
    Measures the amount of light that bounces off a print at 90º angle.
  • Reflective art
    Artwork either line or halftone that is rendered on an opaque surface.
  • Reflective beads
    Minute round particles of glass for embedding in an ink or adhesive film to act as a lens to reflect light rays.
  • Reflective copy
    Illustrative copy that is viewed by light reflected from its surface.
  • Reflective ink
    Ink containing microscopic glass spheres that have the capability of returning light rays to the observer.