This site has not been updated since May 2004. In the rapidly developing world of digital printing, this is a very long time! In consequence, the information found on this website is out of date and may not be accurate, and should be treated with caution.

Definitions of Common Terminology used in this Website

medium: in digital printing, object onto which >colorant gets applied and which carries the final image; can be made up of various layers, including the >substrate and coatings, and can be >laminated after the printing process.

substrate: the single or multi-layered base material of the >medium, which can have a very simple or complex structure and is a carrier for the coating, if present



Note: Definitions marked with * are quoted from Websters New Encyclopedic Dictionary, New York, 1994

absorption: the sucking up or taking up or in by one substance of another, in the case of >colorants: the taking up of energy in form of light

acuity: sharpness

adsorption: the adhesion in an extremely thin layer of molecules (as of gases, solutes, or liquids) to the surfaces of solid bodies or liquids with which they are in contact*

agglomerate: to cluster

aggregate: to cluster in a dense mass

alumina: aluminium dioxide (AlO2)

analog: data consisting of or systems employing continuously variable signals or data, as opposed to discreet steps or levels of >digital data

anion: negatively charged ion; >cation

apparent resolution: resolution of a >hardcopy as it appears to the naked eye of the observer

archival: a term that has been used extensively in conservation literature, but that lacks an internationally accepted definition. general understanding: with characteristics of long term stability (as in: archival quality)

auxochrome: functional group that can be either >organic or salt-forming and is attached to a molecule to modify and/or intensify the color of that substance

banding: in this context, horizontal, parallel lines in an ink jet print caused by a falsely aligned or defective >printhead

binary: relating to, being, or belonging to a system of numbers having two as its base*

bit: shortened form of the term >binary digit, the smallest unit of information that can be stored in a computer

bleed: to wick; >feather

brightness resolution: resolution relating to the number of tonal values in a >digital image

buffer: a substance capable of neutralizing acids, incorporated into many museum boards and >archival paper products

calender: to press paper between rollers in order to smooth its surface

carcinogen: a substance or agent producing or inciting cancer*

cation: positively charged ion; > anion

cellulose: a complex carbohydrate constituting the chief part of the cell walls of plants, yielding many fibrous products, and being commonly obtained from vegetable matter (as wood or cotton) as a white fibrous substance [...]*, used on a large scale for papermaking

chain scission: >scission of a polymer chain

chroma: color saturation, degree of color purity

chromophore: a specific arrangement of atoms leading to >absorption of >photons at specific wavelengths within the >spectrum of a light source

CIE L*a*b*: three-dimensional color definition model with the parameters L*: lightness, a*: range from red to green, b*: range from blue to yellow

CIE Yxy: three-dimensional color definition model representing all colors visible to the average human eye with the parameters Y: lightness, x: amount of red, y: amount of green. usually representation is two-dimensional, excluding lightness Y

cockling: occurs as >cellulose fibers of a paper swell and shift due to >absorption of moisture, resulting in an uneven, wavy surface that often remains even after the paper has lost the excess moisture

colloid: a very finely divided substance that is scattered thoughout another substance, also: a mixture consisting of such a substance together with the substance in which it is scattered*

colorant: a substance, usually a >dye or a >pigment, with the ability to absorb a certain range of wavelengths from visible light, thus reflecting only the non>absorbed wavelengths, which is perceived as color

color depth: >brightness resolution of a digital image, measured in number of >bits / pixel

colorimetry: measurement and determination of colors

conjugation: in >organic chemistry, the presence of double and triple bonds in a molecule

continuous ink jet: an ink jet system in which pressure pulses are generated directly in the >printhead to eject a continuous stream of drops of ink which are consequently seperated into printing and non-printing drops by electrostatic deflection

continuous tone: a color or >monochrome image format or printing process capable of illustrating a gradual and virtually smooth scale of tonal changes

contone: abbreviation for continuous tone

co-polymer: combination of two or more different types of polymer in one molecule

cross-linking: bonds between two or more polymers

curing: to prepare by or undergo chemical or physical processing for keeping or use* (e.g. curing an adhesive with UV-radiation)

digital: data consisting of or systems employing discreet steps or levels, as opposed to continuously variable analog data

disperse: to distribute more or less evenly throughout a medium*

dissolve: to break up a substance into its component parts by uniformly mixing it into a liquid medium

dots per inch (dpi): measurement of output device resolution

drop-on-demand (DOD) / impulse: an ink jet system in which pressure pulses are generated directly in the >printhead by piezo crystals or heated resistors to eject drops of ink only when they are needed to print a dot

dye: a >colorant consisting of single molecules that are able to >absorb certain parts of the >spectrum of visible light and reflect others

excited state: in photochemistry, the state of a molecule after it >absorbs energy

extinction coefficient: also termed absorption coefficient, describes the amount of light of one wavelength absorbed by a molecule

feather: to wick; >bleed

gamut: the limited range of colors provided by a specific >input or >output device, or by a set of >colorants

ground state: in photochemistry, the state of a molecule before it >absorbs any energy

halftone: a method of simulating >continuous tone in >binary printing utilizing overlapping black or color process dots of varying size or position

hardcopy: >digital print on a >substrate; >softcopy

hue: color of an object as perceived by the eye

hydrolysis: a chemical process of decomposition involving splitting of a bond and addition of the elements of water*

impact printing: process of applying >ink to a >substrate utilizing physical contact between some part of the printing device and the substrate, (e.g. >offset, lithography, and flexography); >non-impact printing

ink: substance in ink jet printing (liquid or solid) which gets sprayed onto the >medium; made up of a >colorant, a >solvent, or >vehicle, and various additives

input: information fed into a >digital system

inorganic: in the context of chemistry, refers to substances that do not contain carbon atoms; >organic

ion: an atom or group of atoms that carries a positive or a negative charge as a result of having lost or gained one or more electrons; >anionic; >cationic

kogation: unique to thermal ink jet, caused by thermal de-composition of organic matter and the deposition of those products on the heat element of a thermal >printhead, thereby rendering it useless due to insulation of the heat element

Lab: abbreviation for >CIE L*a*b*

lake: a class of >pigments composed of a soluble dye >adsorbed on or combined with an >inorganic substance such as a metal

laminate: a clear coating of a variety of possible substances, usually plastic, that is applied to one or both sides of a >medium after printing for reasons of protection

lightfast: resistant to the destructive action of light

lignin: >polymer that occurs in the woody cell walls of plants and in the cementing material between them which is easily oxidized to form yellow-brown compounds and acidic products

lines per inch (lpi): measurement of output device resolution

medium: in digital printing, object onto which >colorant gets applied and which carries the final image; can be made up of various layers, including the >substrate and coatings, and can be >laminated after the printing process.

micelle: an >aggregation of molecules that constitutes a >colloidal particle

micron (µm): micrometer, unit of length equal to 10-6 meters

mil: unit of length equal to 10-3 of an inch (0.0254 mm)

molecular weight: weight of one mole (= 6 x 1023 molecules) of a substance in grams

monochrome: single colored

mordant: a chemical that fixes a >dye in or on a substance by combining with the dye to form an insoluble compound*

nanometer (nm): unit of length equal to 10-9 millimeter

non-impact printing: process of applying >ink to a >substrate without utilizing physical contact between some part of the printing device and the substrate, (e.g. ink jet); >impact printing

non-polar: >polar

nozzle: in ink jet printing, the orifice in the >printhead from which >ink droplets are ejected

offset: >analog ink-based printing process, in which ink adhering to a metal plate is transferred (offset) to a blanket cylinder before being applied to the >substrate

opaque: not transmitting light; >transparent

optical density (OD): >print density

organic: in the context of chemistry, refers to substances that contain carbon atoms; >inorganic

output: information fed out of a >digital system in the form of data or >hardcopy

oxidation-reduction: a chemical reaction in which one or more electrons are transferred from one atom or molecule to another*

pH: unit of measurement indicating the acidity or alkalinity of a substance on a scale of 0-14. pH<7 is acid, pH>7 is alkaline, pH=7 is neutral

phase change: an ink jet system in which pressure pulses in the >printhead eject drops of >ink that is in a heated, molten state, and which solidifies when it hits the >substrate

photo-catalysis: the chemical mechanism behind different fading characteristics depending on whether a >dye is alone or makes up a composite color

photon: a quantum (= subdivision of energy) of radiant visible energy

picoliter (pL): unit of volume equal to 10-12 liter

pigment: >colorant consisting of a natural crystalline molecules or an >agglomerate of synthetic >dye molecules

pixel: in the context of ink jet printing, the smallest image forming printed dot on the >medium

plasticiser: a chemical added to substances to impart flexibility, workability, or stretchability

polar: molecule having a dipole or substance characterized by molecules having dipoles, determines solubility characteristics; >non-polar

polyethylene (PE): plastic consisting of >polimerized ethylene

polymer: a chemical compound or mixture of compounds that is formed by polymerization and consists essentially of repeating structural units*

porosity: state of being able to absorb liquids due to pores

print density: or optical density (OD), of an ink jet >hardcopy is the visually perceivable and densitometrically measurable >absorbtion of light on the surface of a hardcopy due to the presence of a >colorant. OD only measures the surface density of a dry hardcopy, not the density of the total amount of >ink that was sprayed onto the >medium.

printhead: part of a >digital printer that is directly responsible for applying >ink to a >medium

print resolution: the >resolution of a >digital print

print-through: >show-through

proof: a test print used for final color correction in the printing industry

rag: in the context of paper manufacturing, cotton rags are a source for high quality >cellulose fibers

RC paper: >resin coated paper

receptor coating: layer adhered to the surface of the >substrate that has the function of receiving and binding >ink that arrives from the >printhead nozzle

recto: front side of an object; >verso

reduction: >oxidation-reduction

refractive index: measurement of the bending (refraction) of light entering a >translucent or >transparent substance

relative humidity (RH): the ratio of the amount of water vapor actually present in the air to the greatest amount possible at the same temperature*

resin: natural >organic substances that are formed especially in plant secretions and are used in varnishes, printing >inks, and >sizing; in this context, any of a large class of synthetic products that have some of the physical properties of natural resins but are different chemically and are used chiefly as plastics*

resin coated paper: or RC paper, term used for photographic paper used in most color and some black and white printing applications, which has a polyethylene coating on each side

resolution: in the >digital context, the capability of making up a larger image out of many small and discrete entities such as pixels; a measure of the greatest amount of detail or sharpness that can be seen in an image

resonance: in photochemistry, the capability of electron vibration in a >conjugated molecule

rosin: a >translucent, amber-colored, brittle, natural >resin that is obtained from pine trees and used in paper >sizing

scission: splitting, or division of a substance or an object; >chain scission

shellac: a purified form of the >resin lac, which is secreted by an insect and which is used for varnishing

show-through: occurs when >ink penetrates the paper >substrate and is visible from the back; also termed print-through

silica: silicon dioxide (SiO2)

sizing: a gluey substance such as a >resin, gelatin, or starch used for finishing, modifying, and filling the pores in a surface such as that of paper

softcopy: view of a file on a monitor screen; >hardcopy

solvent: a usually liquid substance capable of >dissolving or >dispersing one or more other substances*

spectrum: in this context, the full range of visible wavelengths of light energy radiation

substrate: the single or multi-layered base material of the >medium, which can have a very simple or complex structure and is a carrier for the coating, if present

surfactant: substances that enable the >dispersion or >solution of >non-polar molecules in >polar liquids or vice versa

tinctoral strength: measurement of the brilliancy of a >colorant

translucent: allowing light to pass through but >opaque instead of clear

transparent: allowing light to pass through but clear instead of >opaque

vehicle: in this context, a fluid or solid substance, depending on its physical state and on its desired function, that serves to either >dissolve or >disperse another substance or a range of substances and make them usable in a certain environment

verso: reverse side of an object; >recto

viscosity: the tendency of a liquid to flow slowly or quickly resulting from the friction of its molecules

waterfast: resistant to the destructive action of water

wettability: the ease by which a >pigment can be wet by an >ink >vehicle or a >substrate by a liquid

wick: to draw moisture by capillary action; in the context of ink jet printing: the tendency of an >ink to spread along paper fibers resulting in a loss of dot edge sharpness and overall image quality