• A

    • Abrasion Resistance

      ability to withstand the effects of repeated rubbing and scuffing.

    • Abrasiveness

      the tendency of a substance to wear or scratch other surfaces with which it contacts.

    • Absorbency

      the tendency of a porous material, such as paper, to take up liquids or vapors

    • Acetone

      a very volatile solvent used mainly in packaging gravure inks. Acetone is no longer considered a VOC.

    • Acid Number

      a measure of the amount of free acid on a molecule. It is calculated as the number of milligrams of potassium hydroxide required to neutralize the free acids in one gram.

    • Additive Primary Color

      Red, green, and blue. Combined lights of these colors produce the sensation of white light.

    • Adhesion

      the tendency of a material to bond to another material.

    • Adsorption

      the adhesion/penetration of a thin layer of material to the surface with which it is applied.

    • After-Tack

      occurs when an ink film does not fully dry and is still sticky to the touch. Some printed films can develop an after tack after appearing to be dry initially.

    • Agglomerate

      a cluster of undispersed (with inks, usually pigment) particles.

    • Aggregate

      a chain of undispersed (usually pigment) clusters.

    • Alcohol

      a family of volatile organic solvents containing the group C-OH, used in flexographic and gravure inks. The most commonly used in inks include methyl (wood) alcohol, ethyl (grain) alcohol, propyl, and isopropyl alcohols.

    • Aliphatic Hydrocarbon Oils

      organic liquid having a linear or branched hydrocarbon structure. Used as solvent in oil based sheetfed and heatset inks. Available in a variety of boiling ranges.

    • Alkali Blue

      a strong organic blue pigment, available in both a red shade and green shade version. Also called Reflex Blue.

    • Alkyd

      a group of synthetic resins formed by condensation of polybasic acid with polyhydric alcohol, and modified with drying oils for printing ink use.

    • Alumina Hydrate

      a white inorganic pigment used as an extender in inks and noted for its transparency.

    • Aluminum Ink

      (See Silver Ink)

    • Ambient Conditions

      a term used to denote the temperature, humidity, pressure, etc. of the surrounding air.

    • Anhydrous

      containing no water.

    • Aniline Dye

      early name for rubber plate fluid printing ink (now called flexographic) Aniline Point – the minimum temperature at which a hydrocarbon solvent is completely soluble in an equal volume of freshly distilled aniline. Below this point, the mixture is cloudy and separates into two layers. It is used as a measure of solvent power of hydrocarbon solvents.

    • Anilox Roller

      an engraved metering roll used in flexo presses to transfer a controlled film of ink from the fountain roller to the printing plate.

    • Anti-skinning Agent

      chemical substances that retard the skin formation on the surface of an oxidizable oil or ink. They are frequently referred to as antioxidants.

    • Antioxidant

      chemicals that selectively react with oxygen to prevent the oxidation of other substances in the mixture.

    • Aromatic Hydrocarbon Oil

      organic liquids having a conjugated ring hydrocarbon structure. Have a stronger solvency for printing ink resins than the aliphatic hydrocarbon solvents. The amount used in oil-based offset inks is generally minimized due to lack of solvent release needed for fast drying and some environmental concerns with affluent in heat set press ovens.

    • Azeotrope

      a pair of liquids forming a mixture that boils higher or lower than either component.

  • B

    • Ball Mill

      a dispersion device in which round hard balls of various compositions and sizes are placed in a rotating cylinder with the material to be dispersed. When the cylinder rotates, the balls cascade into one another with the product crushed between them. It disperses the material (usually pigment in a vehicle for inks) by impact and attrition as the cylinder revolves.

    • Barrier Coating

      the coating applied to a substrate to make it resistant to the permeation of moisture vapor, gases, water, or other liquids including oils.

    • Barytes

      natural barium sulphate used as an ink pigment and an extender. It is considerably more abrasive and grittier than precipitated barium sulphate.

    • Base

      in ink manufacture, a dispersion of very high pigment-to-binder ratio containing usually only one pigment (or dye) dispersed in a vehicle. This is subsequently mixed with polymers, solvents, and additives to produce the finished ink.

    • Basis Weight

      the weight in pounds of a ream (500 sheets) of paper cut to a given standard size for that grade. For example, 500 sheets 25″ x 38″ of 80-1b. coated for book papers will weigh eighty pounds. Internationally this is expressed in grams per square meter.

    • Bimetal Plate

      in lithography, a plate in which the image area is copper, or brass and the non-image area is aluminum, stainless steel, or chromium.

    • Binder

      the components in an ink film that ensures the pigment adheres to the printed surface.

    • Blanc Fixe

      precipitated barium sulphate used as a semi-transparent extender in printing inks.

    • Blanket

      a natural or synthetic rubber, fabric backed material that is clamped around the press cylinder on an offset press. The blanket transfers the ink from the printing plate to the substrate.

    • Bleach

      the method of measuring the tinctorial strength of an ink or pigment base by mixing a small portion of the material to be tested with a larger amount of white base and evaluating the tinctorial strength of the ink versus a control standard. This was initially done only visually, but today many companies do this instrumentally, usually with a spectrophotometer. Bleed – 1) the spreading or migration of an ink component into an unwanted area. 2) The spreading or running of a pigment color by the action of a solvent.

    • Blend

      a mixture of two or more materials

    • Blinding of Lithographic Plate

      loss of ink-receptivity in the image area of the plate.

    • Blister

      small raised area caused by expansion of trapped gas or liquid beneath the surface. Most common with coated paper.

    • Blocking

      an undesired adhesion between layers of material (that might occur under moderate pressure and/or temperature in storage or use), to the extent that damage to at least one surface is visible upon separation. Can be problematic when printing roll to roll.

    • Bloom

      (Also see Blushing) material migrates to the surface of a film.

    • Blown Oils

      products obtained by blowing air through heated drying or semi-drying oils. This changes the oil by oxidizing the double bonds usually resulting in increased viscosity.

    • Blushing

      (Also see Bloom) a milky or foggy appearance on the surface of a printed ink film or coating due to incompatibility of one of the ingredients. This effect is can also be caused by excessive moisture condensation

    • Board

      a heavy weight sheet of paper or other fibrous substance, usually of a thickness greater than 6 mil (0.006 inch). Also referred to as paperboard.

    • Bodied Oil

      a drying or semi-drying oil whose viscosity has been increased (usually by heating).

    • Body

      1) A general term referring to viscosity, consistency and flow of an ink, ink vehicle or coating. 2) Used to describe the increase in viscosity by polymerization of drying oils at high temperatures (bodying).

    • Body Gum

      linseed oil that has been heat polymerized to a heavy, gummy state. It is used as a bodying agent for some applications.

    • Bodying Agent

      a material added to an ink to increase the viscosity.

    • Boiled Oil

      a drying oil that has been heated to a high temperature for a short time. Such treatment increases the viscosity. Boiled oil sometimes contains a small amount of drier.

    • Boiling Range

      the temperature range where a substance can be distilled. Examples: VM & P Naphtha range of 250 0 to 300 0 F, Magiesol 47 range of 463 to 530.

    • Brightness

      the intensity of whiteness perceived by a viewer. A term to describe paper whiteness and is used as a differentiating factor for paper grades.

    • Brilliance

      the combined effect of brightness, gloss and apparent color strength. Equivalent to “shine” with paints and coatings.

    • Bronze Dusting

      application of finely powdered metal particles or flakes to a wet printed film for special affects applications.

    • Bronze Powder

      a metallic pigment for printing ink, consisting mainly of small particles of copper and brass alloys.

    • Bronze/bronzing

      metallic appearance of a color when viewed at varied angles and illumination. Can be due to the pigment composition, pigment-vehicle incompatibility and/or degree of dispersion. Normally is considered undesirable. Common with alkali blue.

  • C

    • CAB

      (See Cellulose Acetate Butyrate)

    • Cadmium Red

      an inorganic red pigment which is resistant to light, heat and soap. Cadmium red is no longer used in the printing ink industry due to its classification as a toxic heavy metal.

    • Cadmium Yellow

      an inorganic yellow pigment that is resistant to light, heat and soap. Cadmium yellow is no longer used in the printing ink industry due to its classification of a toxic heavy metal.

    • Caking

      (Also see Piling) — build up (accumulation) of material (many times it is pigment) on plates, print cylinders, blankets or rollers that can be due to a number of factors including raw material incompatibility, excessively high solids, over pigmentation, rheological instability, premature drying and the inability of the vehicle to hold the pigment in suspension.

    • Calendar

      a set or stack of horizontal rollers, located either at the end of a paper machine or done off-line, that “polishes” the paper surface as it passes between the roller nips increasing the smoothness and gloss. This process is referred to as calendaring.

    • Caliper

      the thickness of a sheet or material, usually expressed in the U.S. as thousandths of an inch (mils).

    • Capillary Action

      a phenomenon associated with surface tension of a liquid relative to a solid. Examples include the rise of liquids in capillary tubes, the action of blotting paper, and the transfer of inks and coatings from engraved cells to a contacting surface.

    • Carbon Black (Also see Channel Black)

      an intensely black, finely divided, pigment obtained by burning natural gas or oil with a restricted air supply.

    • Carcinogen

      a substance that causes cancerous growth in living tissues.

    • Casein

      a protein usually obtained from milk used in sizing, adhesive solutions, and aqueous inks/coatings.

    • Cast-Coated Paper

      a paper or paperboard in which the coating is hardened or set while in contact with a highly polished surface (usually a large diameter steam-heated chromium surfaced drum). Cast-coated papers have a high gloss and smooth finish.

    • Catalyst

      a substance that increases the rate of a chemical reaction without being permanently altered by the reaction. Metallic driers act as catalysts in oxidative drying inks.

    • Catalytic Coating

      coatings formulated as two-part systems, available in both water and solvent reducible formulas. Based on reactive resins that cure to form a thermoset film. These coatings have good heat and abrasion resistance, high gloss, solvent resistance and adhere to a wide variety of substrates.

    • Cell

      a small etched or engraved depression in a gravure cylinder or flexo anilox roller that carries the ink.

    • Cellophane

      transparent flexible film consisting of regenerated cellulose and plasticizers.

    • Cellosolve

      trade name for ethylene glycol monoethyl ether. A relatively slow evaporating solvent used as a retarder in flexographic inks.

    • Cellulose Acetate

      a clear thermoplastic material, usually in film form, made from cellulose and acetic acid.

    • Cellulose Acetate Butyrate (CAB)

      a clear thermoplastic material, either as a film or liquid form, made from cellulose, reacted with both acetic and butyric acids. Used as a packaging film, as well as a polymer in liquid inks.

    • Centipoises

      a unit measure of viscosity. One hundred centipoises equals one poise. Water has a viscosity of one centipoise.

    • Chalking

      a undesirable condition of a printing ink in which the pigment is not properly bound to the substrate by the vehicle and can be easily rubbed off as a powder. Sometimes referred to as powdering.

    • Channel Black (Also see Carbon Black)

      carbon black produced by impinging a natural gas flame against a metal surface. Due to air pollution control requirements, this type of black has been almost completely replaced by furnace black in the U.S.

    • China Clay

      natural white inorganic mineral pigment used in paper coatings and as an ink extender. Also known as kaolin. Pigment White 19.

    • Chroma

      one of the attributes of color, characterized by purity or saturation (strength).

    • Chrome Yellow

      a light resistant opaque yellow pigment composed essentially of lead chromate. No longer used in printing inks due to toxicity issues.

    • CIE L*a*b

      scale adopted by the International Commission on Illumination (CIE) to serve as a global standard for color measurement.

    • Cobalt Drier

      a material containing chemically combined cobalt used to accelerate oxidation and polymerization of oil based inks. Referred to as a top drier.

    • Cohesion

      the tendency of a material to bond to itself rather than another material.

    • Cold Set Inks

      a term usually applied to news inks indicating that no heat is applied on the press. These inks are also referred to as non-heat set inks.

    • Color Burn-Out

      an objectionable change in the color or intensity of a printing ink that may occur either in bulk form or on the printed sheet. In the former case, it is associated primarily with specific pigments and/or tints. Can be caused by a chemical reaction between components in the ink formulation. In the former case, it is generally caused by heat generated (oxidative drying is exothermic) in a pile of printed material during drying or incompatibility with an aqueous or UV coating.

    • Color Control Bar

      a patterned image designed to provide areas that can be used to measure and monitor a number of important printing parameters during the print run. These parameters have a large impact on print quality and typically include print density, dot gain, trapping efficiency and print contrast. A densitometer, image analyzer, colorimeter or color spectrophotometer can be used, but most printers rely on a densitometer
      There are a number of different color bar designs available from FOGRA, GATF, RIT and other organizations. Usually consists of individual solid areas for each color, overprints of two- and three-color solids, screens (25, 50 & 75 %), registration targets, resolution targets, slur bar, gray balance, others that can be customized as required. Some systems allow for automatic measurements while the press is running. Printed in an area of the sheet that will be trimmed off during the finishing process.

    • Color Process

      a process used for the reproduction of an original by color printing created by the color separation process in which the original image is broken down into the primary colors to produce individual progressives (also referred to as progs). This allows for the creation of a separate printing plate for each color. These are recombined during the printing process on the press to produce the complete range of colors of the original.

    • Color Proofs

      prints that are used to verify that the original images are being reproduced correctly before starting the actual press run. Early on this was done on a proofing press, but today the most popular method is using nonimpact printers

    • Color Separation

      using red, green, and blue filters to divide the colors of a multicolored original into three process colors and black. The four resulting film intermediates are used to prepare the yellow, magenta, cyan, and black printing plates. Color separation can be accomplished by exposing the original film or other image to an electronic color scanner, but today is done with computer software. Initially the process involved camera work and color filters followed by film contacting.

    • Color Standard

      a wet ink sample or printed proof, to which another similar material is compared. Control sample.

    • Color Strength (Tinctorial Strength)

      the effective concentration of coloring material per unit of weight or volume of a printing ink.

    • Colorant

      the components of an ink that provide color that may be a pigment or a dye or a combination of the two.

    • Colorfastness

      (See Lightfastness)

    • Compatibility

      the ability of two or more differing materials to be mixed together without resultant kick-out or haziness.

    • CONEG

      regulations proposed by the Coalition of Northeastern Governors, and enacted by many states, that limit lead, mercury, cadmium, and hexavalent chromium to 100 ppm total in packaging materials, including inks.

    • Continuous Tone

      the form of an image in which changes of density from element to element are smooth and without steps, as contrasted to halftone images in which density changes are represented by steps in halftone dot size.

    • Copolymer

      polymer produced from a combination of two or more monomers.

    • Copy

      material, including art and text, submitted for reproduction. The term is also used to refer to the final printed result.

    • Corrugated Board

      a composite paper product made by applying a liner to each side of a fluted or corrugated inner sheet or medium. The liner is usually made from kraft board, and the corrugated medium is made from neutral sulfite or recycled board.

    • Cover Inks

      inks formulated to print magazine or book covers. These inks require exceptional scuff resistance, high gloss, and resistance to skin oil.

    • Coverage

      usually refers to the amount of ink printed (amount of image area versus nonimage area) on a substrate. Also referred to as Total Coverage Area (TAC) that is expressed as a percentage.

    • Crawling

      the contraction of an ink film after printing on a surface due to poor “wetting” of the surface.

    • Crocking

      smudging or rubbing off of a printed ink film.

    • Cure/Curing

      chemical conversion of a wet coating or printing ink film to a solid film.

    • Curl

      in paper, distortion of the unrestrained sheet due to differences in structure or coatings from one side to the other. The curl side is the concave side of the sheet.

    • Cut

      1) An expression commonly used to designate an engraving. 2) To dilute an ink, lacquer or varnish with solvents or with clear base.

    • Cyan

      process blue made with phthalocyanine pigment

  • D

    • Dampening Solution

      (See Fountain Solution)

    • Dampening System

      a roller system designed to distribute the fountain solution to the plate evenly and in a controlled fashion.

    • Deflocculation

      the dispersion of pigment clusters, or “flocks”, into smaller units in an ink.Dehydrated Castor Oil a castor oil chemically treated to improve its drying qualities.

    • Delamination

      the separation of layers of a laminate.

    • Densitometer

      an instrument that measures the intensity of light reflected from a surface. It is used as a control instrument during printing to check the uniformity and intensity of print color.

    • Desensitize

      treating non-image areas of a lithographic plate to make them water-receptive and ink-repellent. This is usually accomplished with a solution of gum arabic.

    • Diarylide Yellow

      a strong organic yellow pigment used in offset process yellow and many other types of printing inks, includes AAA, AAOT, AAMX, etc

    • Dilatancy (Shear Thickening)

      the increase in apparent viscosity with increasing shear.

    • Diluent

      a liquid used to thin (reduce viscosity) of an ink or varnish.

    • Discharge

      1) Removal of material from a mixing vessel into a storage tank or shipping container. 2) The accidental or intentional spilling, leaking, pumping, pouring, emitting, emptying or dumping of hazardous wastes into the environment.

    • Dispersing Agent

      chemicals added in small amounts to facilitate dispersion of a pigment into a liquid medium. Also referred to as wetting agent.

    • Dispersion

      a uniform distribution of solid particles in a carrier liquid, generally obtained by mixing or milling.

    • Distributing Rollers

      press rollers that convey or transfer ink from the ink fountain through a series of rollers (roller train) to the form roller and printing plate

    • Doctor Blade

      in gravure or flexographic printing, a blade that scrapes off the excess ink from the surface of the etched cylindrical roll/anilox roll just prior to printing, leaving the “cells” filled with ink and the “land” areas free of ink.

    • Dot

      the individual element of a halftone

    • Dot Gain/Dot Spread

      increase in the size of the printed dots that includes both the process of recreating the dot from film to the plate and plate to the substrate. This phenomena is part of the reproduction process and most printing methods have specifications for acceptable levels of dot gain. In recent years it is referred to as Tone Value Increase (TVI)

    • Double-tone Ink

      a type of printing ink that produces the effect of two-color printing with a single impression. These inks typically contain an insoluble pigment and a soluble toner/dye that bleeds upon printing to produce a secondary color.

    • Drawdown

      a film of ink deposited on a substrate to allow evaluation of the undertone and masstone of the ink.

    • Drier Dissipation

      a loss in catalytic power of a drier due to a physical absorption or a chemical reaction with a component in the ink, primarily pigments.

    • Driers

      organic metal compounds that act as catalysts for the oxidative drying process.

    • Drop on Demand Ink Jet

      a nonimpact printing method in which ink droplets are emitted only
      when required for imaging.

    • Dry Color

      a pigment in powder form

    • Dry Offset (Letterset)

      a process that utilizes a relief plate to transfer ink to an offset blanket and then to the substrate without the use of fountain solution/water.

    • Drying In

      a situation where ink dries prematurely in either the cells of an anilox
      (flexographic) roller or a gravure cylinder that only allow partial filling. This leads to reduced print density and loss of image detail.

    • Drying of Ink

      the conversion of a wet ink film to a solid state. This can be accomplished by oxidation, evaporation, polymerization, penetration, gelation, precipitation, and combinations thereof.

    • Drying Oils

      liquid products that are composed of enough unsaturation to enable oxidative drying.

    • Drying Time

      the amount of time required for a printed ink film to form a tack-free surface

    • Ductor Roller

      a printing press roller that is in intermittent contact with another roll which can be located in the ink distribution system or non-integrated dampening system.

    • Dye

      colorant material that is soluble in a vehicle or solvent. (versus pigments that are insoluble).

  • E

    • Effluent

      waste material, such as liquid industrial waste or sewage. May or may not be discharged into the environment. This term is many times used in reference to water pollution.

    • Efflux Cup/FIow Cup/Dip Cup

      utilized to measure the viscosity of liquids by recording the time required for the material to empty through the cup orifice. Examples are Zahn or Shell
      cup which are assigned numerical values based on the size of the orifice. Many times is
      used press side to make viscosity adjustments.

    • Elastomer

      rubber-like substance or polymer.

    • Electromagnetic Spectrum

      the entire range of wavelengths or frequencies of electromagnetic radiation with the shortest being gamma rays and the longest radio waves.

    • Electron Beam

      a continuous stream of electrons used to cure or cross link oligomers/monomers in radiation curable inks and coatings.

    • Electrostatic Assist (ESA)

      a method of applying a high-voltage, low amperage, charge to the gravure impression roll to significantly improve ink transfer from the cells to the substrate.
      Its use can minimize print defects associated with lack of ink transfer.

    • Electrostatic Printing

      nonimpact printing based on electrostatic principles. It involves the use of a dielectric image, stencil, or facsimile scanning ion source to form the image.

    • Emulsification

      in lithography, it refers to the ink-fountain solution interaction to form a mixture (water in ink emulsion) that is required for the lithographic process to take place. Over emulsification (ink in water emulsion) and total repellence (no emulsification takes place) both result in a failure to lithograph.

    • Emulsifying Agent

      chemicals used to facilitate the development of emulsions and to improve emulsion stability.

    • Emulsion

      a mixture of two mutually insoluble liquids in which one liquid is finely distributed as droplets in the other. An example is the latex emulsions used in flexographic inks.

    • Environmental Protection Agency (EPA)

      the agency charged with implementing and enforcing environmental regulations. Eosine (See Phloxine)

    • EPA Hazardous Waste Number

      the number EPA assigns to each waste that is considered hazardous.

    • EPA Identification Number

      the number EPA assigns to each waste generator, transporter and treatment, storage, or disposal facility.

    • Ester

      the reaction product of an organic acid and alcohol. Examples are ethyl acetate solvent and butyl phthalate plasticizer.

    • Ester Gum

      the glycerol ester of rosin. It is used as an ingredient in some printing ink varnishes.

    • Etching

      1) In lithography, the use of acidic substances (fountain solution) to treat the non-printing areas of a metal printing plate making it receptive to the fountain solution 2) In engraving, a treatment with acid or by mechanical means to create a recessed image area.

    • Ethyl Acetate

      a volatile ester solvent used in flexographic and rotogravure inks.

    • Ethyl Cellulose

      a film forming polymer used in the manufacture of solvent based flexo and gravure inks

    • Evaporation

      process of going from a liquid to a gaseous or vapor state. In printing inks it refers to the solvent leaving the printed ink film.

    • Extender

      a transparent or semi-transparent white pigment or varnish used to reduce the color strength of an ink while maintaining the rheology.

    • Exudation

      the migration of solid material(s) to the surface of a film.

  • F

    • Fade-O-Meter

      an instrument used to measure the light-fastness or resistance to fading of a printed ink film. This is done exposing the print to a carbon or xenon light source.

    • Fading

      the change in strength or color upon exposure to light, heat, moisture, temperature extremes or combinations thereof.

  • P

    • Plate Swelling

      increase in caliper of a rubber or polymer flexographic plate due to an interaction with a solvent or other component of the ink.

    • PMA

      an abbreviation used to describe a pigment that has been precipitated with phosphomolybdic acid to give it permanence and insolubility.

    • Poise

      a unit of measure of viscosity. One hundred centipoises.

    • Polar Solvent

      solvent with oxygen molecules. Examples are water, alcohols, esters, and ketones.

    • Polyamides

      polymers containing amide groups (NH3) that are widely used in liquid inks for films and foils.

    • Polybasic Acids

      acids having two or more carboxyl, or COOH, groups per molecule, such as maleic, succinic and phthalic acids

    • Polyethylene

      a synthetic resin of high molecular weight resulting from the polymerization of ethylene gas under pressure. Used as a film for packaging.

    • Polyhydric Alcohols

      alcohols containing more than one C-OH group per molecule such as glycols and glycerol (glycerin). These alcohols are considerably less volatile than the monohydric alcohols.

    • Polymer

      a large molecule (or macromolecule) composed of many monomers.

    • Polypropylene

      a synthetic resin of high molecular weight resulting from the polymerization of propylene gas. Frequently used as a film for packaging.

    • Polystyrene

      a thermoplastic material derived from the polymerization of styrene.

    • Polyvinyl Acetate

      a resin prepared by the polymerization of vinyl acetate.

    • Polyvinyl Alcohol (PVA)

      a family of resins produced by hydrolysis of polyvinyl esters, such as polyvinyl acetate.

    • Polyvinyl Chloride (PVC)

      a family of resins produced by polymerization of vinyl chloride.
      Most PVC resins are copolymers of vinyl chloride with small amounts of vinyl acetate.

    • Polyvinyl Chloride Acetate

      a family of resins produced by co-polymerizing a mixture of vinyl chloride and vinyl acetate.

    • Polyvinylidene Chloride (PVDC)

      a thermoplastic material produced by the polymerization of vinylidene chloride. Also known as Saran. PVDC provides an excellent oxygen and moisture vapor barrier.

    • Presensitized Plate

      a metal or paper plate that has been precoated with a light-sensitive coating, e.g., a presensitized lithographic plate.

    • Printability

      a collective term used to describe the properties required of all components in a printing process.

    • Printing Ink

      a pigmented material used to generate a visible image. Used for the mechanical application, impressing, stamping, or transferring to paper and other substrates such as wood, fabrics, plastics, films or metals

    • Printing Plate

      the image carrier for the printing process. Ultimately transfers the ink directly or indirectly to the material to be printed.

    • Printing Press

      a mechanical device or machine used to reproduce an inked image, pattern or design onto a substrate.

    • Prior Sanctioned

      ingredients considered safe prior to 1938 (when the FDA was established) and unquestioned for use in foods. These substances are exempt from FDA additives regulation.

    • Process Inks

      inks used in the modern method of reproducing images by a color separation process. The colors used are yellow, magenta (red), and cyan (blue). Black is normally added to color dark areas and provide contrast.

    • Progressive Proofs (Also see Color Proofs)

      in color separation, a series of proofs of a color process reproduction of each color, and in combinations of two, three, and four colors. Used to indicate color quality and as a guide for printing. Also called progs. Today this is commonly done with nonimpact printers.

    • Proof

      a control print, test print or trial impression used for evaluation to ensure the printed job meets all the required criteria.

    • Prussian Blue

      a red shade iron blue pigment.

    • PTA

      an abbreviation used to describe a pigment that has been precipitated with phosphotungstic acid to give it permanence and insolubility.

    • PVA

      (See Polyvinyl Alcohol)

    • PVC

      (See Polyvinyl Chloride)

    • PVDC

      (See Polyvinylidene Chloride)

  • Q

    • Quick-Setting Inks

      inks for letterpress and offset that dry by either filtration, coagulation, selective absorption or often a combination thereof. The vehicles are generally special resin-oil combinations that upon printing, separate into a solid material that remains on the surface as a dry film and the fluid portion penetrates rapidly into the stock.

    • Quickpeek

      commercial name for a simple laboratory device to reproduce offset or letterpress ink films. Consists of a metal plate with two different size holes that are filled as a means of measuring a consistent amount of ink, a small rubber roller and ink roll out area.
      Inked roller is used to transfer the ink to the substrate.

    • Quinacridone Red and Magenta

      red pigments of outstanding lightfastness and other resistance properties. Used as substitutes for less permanent reds Red Lake C – a warm, bright red pigment used in printing inks.

  • R

    • Reducers

      varnishes, solvents, oils or compounds used to reduce viscosity of an ink.

    • Reflex Blue

      (See Alkali Blue)

    • Register

      proper alignment of all the printed images created by multiple plates, such as in
      process printing. When successful it is referred to being “in register.” If it is not in register the
      image will appear to be out of focus without any sharp definition.

    • Relative Humidity

      the amount of moisture, i.e., water vapor, present in the air, expressed as a percentage of the amount of moisture required to saturate the air at a given temperature.

    • Repeat

      the printing length of a plate cylinder as determined by one revolution of the plate cylinder gear.

    • Reprography

      the arts and sciences involved in the copying and duplicating of information by any of several processes, in relatively low volume quantities.

    • Resin

      a solid or semi-solid organic substance used as a binder in printing ink vehicles.

    • Retarders

      materials added to slow the drying rate of printing inks. High boiling solvents are sometimes added to slow the evaporation rate.

    • Reverse Print

      printing on the underside of a transparent film.

    • Reverse Type

      letters and words are the nonimage area surrounded by a solid print area of a contrasting color. Example, black solid with white type.

    • Rheology

      the flow and deformation of matter.

    • Rhodamine Red

      a class of clean, blue shade organic reds. Formerly used in process reds, but the high cost has limited this pigment to special color matches. Will burn out under aqueous and UV coatings.

    • Roll-Out

      applying ink via a roller to form a thin film in order to create a print that will be at a thickness similar to the commercial application.

    • Rosin

      a natural resin obtained after removing the turpentine from the sap of a southern pine tree (gum rosin). Also obtained from logs and stumps of the same tree by solvent extraction (wood rosin).

    • Rosin Oil

      an oil obtained from the destructive distillation of rosin.

    • Rotogravure

      (See Gravure)

    • Rub Tester

      a mechanical instrument used for the determination of rub or scuff resistance of a printed ink film by using a timed controlled contact (rubbing action) between two surfaces (usually paper). Examples are the Sutherland Rub tester, Comprehensive Abrasion tester (CAT) and Prufbau Rub Tester.

    • Rule 66

      the original air quality control regulation enacted by Los Angeles County in California for the purpose of eliminating smog caused by the photochemical degradation of some organic solvents. This rule has been used as a pattern for other air quality regulations. Screen – those areas of a printing plate or print compromised of a percentage of dots to reproduce tonal gradations.

  • S

    • Screen Printing

      a process by which an image is transferred to a substrate by squeezing the ink through the unblocked areas of a stenciled metal or polymer screen. Sometimes referred to as silk screen, as silk was the original composition of the stenciled screen. Scumming – 1) Sensitization of the non-printing areas of a lithographic plate resulting in undesirable adhesion of the ink to these areas. 2) In gravure printing, it refers to the deposit of ink in the nonimage area of the cylinder and/or print normally associated with poor wiping by the doctor blade.

    • Setoff

      an undesirable transfer of ink from a printed sheet to another sheet following in the pile or to the back of the web when running roll to roll.

    • Setting of Ink

      the initial phase of the drying process (surface dry) wherein printed sheets, though not fully dry, can be handled without smudging

    • Shade

      1) Color descriptor commonly used as a synonym for hue. 2) In some color systems, a gradation of color resulting from the addition of a small amount of black or a complementary color. (“shade” the color over)

    • Shear

      the relative movement of adjacent layers in a liquid or plastic during flow.

    • Shear Thickening

      (See Dilatancy).

    • Shear Thinning (Thixotropy)

      the decrease in viscosity with increasing shear rate (exhibited by most printing inks).

    • Shelf Life

      the storage stability of a material whereby it does not change from its original state over a period of time.

    • Shellac

      an alcohol-soluble natural resin used in flexographic inks.

    • Shortness

      a rheological property of a printing ink that is characterized by a lack of flow.

    • Shortness Ratio

      the ratio obtained by dividing the yield value by the viscosity when using a falling rod viscometer.

    • Show-Through

      an undesirable condition in which the printed image and/or type can be seen on the reverse side of a sheet under normal lighting conditions.

    • Sienna

      a red variety of iron oxide pigment.

    • Signature

      a printed sheet taken from the press. Also referred to as an impression.

    • Silver Ink

      a printing ink whose principal pigment consists of aluminum powder or flakes. Size — 1) The treatment of paper or paperboard to provide desired functional characteristics, such as hold out, improved printability, water repellency and grease resistance. 2) An ink or coating that dries with a sticky surface that is receptive to the addition of metallic or other powders to create special effects.

    • Slip

      the degree of friction encountered when a surface comes into contact with another surface. Can be measured by the use of a coefficient of friction (COF) test instrument

    • Slip Compound

      an ink additive that imparts lubricating qualities to the dried ink film.

    • Slip Sheet

      a sheet of paper (sometimes treated with a special release coating) placed between two freshly printed sheets to prevent setoff or blocking.

    • Slur

      a condition caused by slippage at the moment of impression between any two of the following: paper, printing plate or blanket.

    • Smearing

      1) the spreading of ink over areas of the plate where it is not desired. 2) ink smudges when a freshly printed signature is handled before it has had sufficient time to dry.

    • Soap Resistance

      the ability to withstand contact with soap. It is a property required of inks used in printing soap wrappers and labels for liquid soap containers.

    • Softening Point

      temperature at which a material begins to deform with no externally applied load.

    • Solid

      a printed area uniformly and completely covered with ink.

    • Solvent

      a material, usually a liquid, capable of dissolving another substance, usually a solid, to form a solution.

    • Solvent Release

      the evaporation of a solvent from the printed ink film during drying. Influenced by the interaction of the polymers and solvents, as well as the solvent evaporation rate.

    • Solvent Retention

      a portion of the ink solvent remains in the dried printed ink film. High solvent retention may be responsible for an odor to the printed product. Also, high solvent retention may result in resoftening of the dried film that can lead to blocking.

    • Soya Bean Oil

      a semi-drying vegetable oil used in oil based printing inks.

    • Specific Gravity

      the ratio of the weight of a given volume of a material to the weight of an equal volume of water at a specified temperature.

    • Spectrophotometer

      an instrument for measuring color values by the relative intensity of each of the component spectrum wave lengths. More broadly, this instrument identifies the color by measuring the absorption (or reflection) of electromagnetic radiation of organic and inorganic substances. Visible spectrum analysis is commonly used in absolute color measurement.

    • Spreading

      a thickening or enlarging of printed areas caused by bleeding or lateral movement of ink.

    • Stand Oil

      a drying oil that has been partially refined by allowing certain impurities to settle out after heat treatment. Generally used in the United Kingdom to describe linseed oil.

    • Static

      bound electric charges on the surface of an insulating material.

    • Stock

      paper or other material to be printed.

    • Strike-Through

      the penetration of a printing ink through the sheet, so that the ink is apparent on the opposite side.

    • Stringiness

      the characteristic of an ink that causes it to draw into filaments or threads when worked up on a bench top with ink knives.

    • Stripping

      a condition in which the ink fails to adhere and distribute uniformly on the press rollers (normally the metal rollers).

    • Sublimation

      the changing of a substance from the solid state (or phase) directly to the vapor phase and its subsequent condensation, as a solid, on a relatively cooler surface.

    • Substrate (See Stock)

      the base material that is printed and/or coated.

    • Subtractive Primary Colors (see additive primary colors)

      yellow, magenta and cyan, the hues used for process color printing inks. When combined, these colors give the appearance of black.

    • Sulphate Pulp

      paper pulp made from wood chips cooked under pressure in a solution of caustic soda and sodium sulfide. Also referred to as Kraft.

    • Sulphite Pulp

      paper pulp made from wood chips cooked under pressure in a solution of bisulphite of lime.

    • Supercalender

      a calender stack, not part of the paper machine, with alternate metal and resilient rollers, used to produce a high finish to paper.

    • Supercalendered Paper (SC)

      uncoated grade of paper that is highly calendered to attain a higher gloss than other uncoated grades. Used for newspaper inserts and some magazines. SWOP (Specifications for Web Offset Publications) – a set of standards for color separation films and color proofing developed for publications printers.

    • Sympathetic Ink

      a novelty ink that becomes visible only after special treatment.

    • Synthetic “Papers”

      non-cellulosic “papers” which are film-based. The main plastics used for this purpose are polystyrene, polypropylene, high-density polyethylene and polyvinyl chloride.

  • T

    • Tack

      a relative measurement of the cohesion of an ink film that is responsible for its resistance to splitting between two rapidly separating surfaces. (such as a roller nip)

    • Tackoscope (See Inkometer)

      a type of inkometer manufactured in Europe. Numerical values do not correlate to other tack meters.

    • Tall Oil

      a mixture of fatty and rosin acids obtained as a by-product of a sulfate paper making process and used in the production of printing ink resins.

    • Tall Oil Rosin

      a widely used rosin in printing ink resins.

    • Tap-Out

      a spot of ink applied to paper by a finger using tapping action to distribute the ink to approximately printing film thickness.

    • TDA (Tridecyl Alcohol)

      used as a “sweetener” in oil-based vehicles and inks. Will increase resin solubility. Used in small amounts.

    • Tensiometer

      an instrument used to measure surface and interfacial tensions of liquids.

    • Thermal Printing

      (See Heat Transfer Printing)

    • Thermography

      printing process in which the ink, while still wet on the sheet, is dusted with a resinous powder that adheres to the ink. The sheets are then put through a heating process that causes the particles of powder to fuse together with the ink, giving a raised effect to the letters that simulates steel-die engraving.

    • Thermoplastic

      solid materials that are capable of softening or melting repeatedly when heat is applied.

    • Thermosetting Ink

      ink that polymerizes to a permanently solid and infusible state upon the application of heat.

    • Thinners

      solvents, diluents, low viscosity oils and vehicles that are added to inks to reduce viscosity.

    • Thixotropy

      the property of a liquid or plastic material that involves a reversible decrease of viscosity with time as the material is agitated or worked. It is generally attributed to a loose structure of the dispersed solid particles, which breaks down under agitation.

    • Tinctorial Strength

      the relative ability of a pigment or dye to impart color intensity to a printing ink.

    • Tint

      1) A light color made by adding a large amount of extender or opaque white to a small amount of colored ink. 2) A color that has been printed in a dot or line pattern rather than as a solid.

    • Tinting (or Washing)

      in lithography, a uniform discoloration of the background caused by the bleeding of the pigment in the fountain solution.

    • Titanium Dioxide

      a very opaque white inorganic pigment used in inks and paints.

    • Toner

      1) A highly concentrated pigment and/or dye, used to modify the hue or color strength of an ink. 2) Ink used for nonimpact printing; can be liquid or solid.
      Toptone (See Masstone)

    • Toptone

      (See Masstone)

    • Transparent Inks

      inks that permit transmission of light, thus allowing previous printed ink film or substrate to show through. A required attribute for process printing.

    • Trapping

      printing a wet ink film over previously printed (dry or wet) ink. Dry trapping is printing wet ink over dry ink. Wet trapping is printing wet ink over previously printed wet ink.

    • Tristimulus Values

      color measurements based on the primary colors: yellow, magenta, and cyan.

    • Tung or Chinawood Oil

      a vegetable drying oil having exceptional drying properties, film forming properties and chemical resistance. Tends to yellow upon drying, which restricts its use to dark colors.

    • Two-Part (Two Pot) Systems

      inks or coatings in which two reactive components are mixed together press side.

    • TXIB diisobutyrate)

      used as a “sweetener” in oil based vehicles and inks. Will increase resin solubility. Used in small amounts.

    • Typography

      (See Letterpress)

  • U

    • Ultraviolet Curing ( UV)

      conversion of a wet coating or printing ink film to a crosslinked solid film by the exposure to a ultraviolet light source.

    • Umber

      a brown variety of iron oxide pigment.

    • Undercolor Removal (UCR)

      the reduction of dot percentages of cyan, magenta, and yellow inks in dark neutral areas and replacing the lost density by the black ink.

    • Undertone

      the color of a thin film of ink as seen on a white background. The appearance of an ink when viewed by light transmitted through the film.

    • Universal Product Code (UPC)

      a rectangular bar code of vertical lines of varying thickness that can be read in any direction. Adoption of this code has automated a large number of operations in many industries.

  • V

    • Varnish

      a liquid solution or dispersion of resinous substances in a solvent. Sometimes referred to as a vehicle.

    • Vehicle

      a liquid material used in inks that binds (provides adhesion) and carries the pigment to the substrate. Sometimes referred to as a varnish. Victoria Blue – a clean, red shade organic blue pigment.

    • Viscometer

      instrument used to measure the rheology of materials.

    • Viscosity

      the resistance of a material to deform or flow.

    • VOC (Volatile Organic Compound)

      any organic compound that can significantly participate in photochemical reactions. Some solvents used in the printing industry are among those chemical substances that are subject to governmental regulations because of VOC emissions.

    • Volatility

      the transition phase of a solid or liquid material into the vaporous state at a given temperature.

  • W

    • Washout Inks

      inks used on textiles that are easily removed by washing.

    • Washout Test

      a method of determining the presence of over sized particles and/or contamination in an ink or raw material. The material is first diluted and then passed through a screen (normally 325 mesh). A visual check of the screen determines if there is an excess of large particles. The screen can be weighed before and after to calculate the weight or the percentage by weight of the residue

    • Washup

      the process of cleaning the components of a press that typically includes the rollers, blankets, plates and ink fountain.

    • Water Based Inks

      inks containing a vehicle whose binder is water soluble or water dispersible.

    • Water Vapor Transmission Rate (WVTR

      the rate of water vapor transmission through a material.

    • Weather-O-Meter

      a fadeometer equipped with an intermittent water spray to simulate accelerated weathering effect on a printed sample.

    • Web

      a roll of any substrate that passes continuously through a printing press.

    • Web Temperature

      the temperature of the paper web in the oven (dryer) as differentiated from the oven air temperature

    • Wet Printing (or Wet-on-Wet Printing)

      printing over a previously printed wet ink film.

    • Wetting

      the interaction between the surface of a liquid and the surface of a solid or another liquid. The wetting properties depend on the surface tension of liquids and the interfacial tension between liquid and solid, or between the liquids.

    • Wetting Agents (Dispersants)

      materials added in small amounts to facilitate the dispersion of one material in another.

    • Wipe-on Plate

      a lithographic plate on which a light-sensitive coating is wiped on or applied mechanically.

    • Wire

      an endless finely woven belt (plastic, metal or fabric) on a paper machine on which a pulp solution (typically less than 1% solids) is deposited during the initial stage of the paper making process.

    • Wire Side

      the bottom surface of a sheet of paper that directly contacts the screen during the paper making process. The topside of the sheet is known as the “felt” side. Work and Tumble (See work and turn)

    • Work and Turn

      in the sheetfed printing process, to print one side of a sheet of paper, then turn the sheet over and print the other side.

    • WVTR (See Water Vapor Transmission Rate) Yield Value

      the minimum force required to produce flow. Used as a measure of the flow of an ink at low rates of shear. The falling rod viscometer is the primary instrument used in the ink industry for obtaining the numerical data.

  • Z

    • Zahn Cup

      a type of dip cup for measuring the viscosity of a liquid

    • Zinc Oxide

      opaque inorganic white pigment.

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