| Calendered |
A
film or paper manufactured by passing solid sheets of material between
two polished rollers under high pressure. Mesh is also modified
by this process. The rollers flatten the knuckles on one side to
reduce Theoretical Ink Volume and hence film thickness. |
| Catalyst |
A
substance which has the capability of initiating or accelerating
the speed of a reaction between two or more substances when introduced
into their presence, normally in small quantities. It remains chemically
unchanged at the end of the reaction. |
| Chalking |
The
formation of a powdery coating on the surface of an ink film caused
by disintegration of the binding medium due to disruptive factors
during weathering. |
| Chroma |
A measure of saturation associated with colour. |
| Chromatic |
Perceived
as having a hue; not white, grey or black. Chromatic Attributes
Those attributes associated with the spectral distribution of light. |
| Chromaticity |
That
part of colour specification that does not involve illuminance.
Chromaticity is two-dimensional and is specified by pairs of numbers
such as dominant wavelength and purity. |
| Chromaticity
Co-ordinates, CIE |
The
ratios of each of the three tristimulus values X, Y and Z in relation
to the sum of the three: designated as x, y and z respectively.
Sometimes referred to as the trichromatic coefficients. |
| Chromaticity
Diagram, CIE |
A
two-dimensional graph of the chromaticity co-ordinates, x as the
abscissa and y as the ordinate, which shows the spectrum locus (chromaticity
co-ordinates of monochromatic light, 380-770nm). |
| Chrominance |
The
portions of a signal that are dedicated to describing the hue and
saturation. Used in measuring the difference between two colours
of equal brightness. |
| CIE
(Commission International de l’Eclairange) |
A
set of colour standards based on mathematical modelling of human
vision and light. CIE colour spaces are used for the communication
of colour independent of a specific device. |
| CIE
Chromaticity Co-ordinates |
The
ratios of each of the tristimulus values of a colour to the sum
of the tristimulus values. In the CIE systems they are designated
by x, y, and z. |
| CIE
LAB (L*a*b*) |
A
colour model to approximate human vision. The model consists of
three variables: L* for luminosity, a* for one colour axis, and
b* for the other colour axis. |
| CIE
Luminosity Function (y) |
A
plot of the relative magnitude of the visual response as a function
of wavelength from about 380 to 780 nm, adopted by CIE in 1924. |
| CIE
Standard Illuminates |
Known
spectral data established by the CIE for four different types of
light sources.
CIE Standard Observer A hypothetical observer having the tristimulus
colour-mixture data recommended in 1931 by the CIE for a 2' field
of vision. A supplementary observer for a larger 10' field was adopted
in 1964. |
| CIE
Tristimulus Values |
The
amounts of the three reference or matching stimuli required to give
a match with the colour stimulus considered, in a given trichromatic
system. |
| CIE
xy Chromaticity Diagram |
A
two-dimensional graph of the chromaticity co-ordinates, x as the
abscissa and y as the ordinate, which shows the spectrum locus (chromaticity
co-ordinates of mono-chromatic light, 380-770nm). |
| CIELUV
(or CIE L*u*v*, CIE Luv) |
Colour
space in which values L*, u*, and v* are plotted at right angles
to one another to form a three-dimensional co-ordinate system. Equal
distances in the space approximately represent equal colour differences. |
| Cissing |
A
defect in which a wet ink or varnish recedes from small areas of
the surface leaving either no coating or an attenuated one. (See
reticulation). |
| Cliché |
Used
in pad printing. The "inkable" steel or nylon plate that
is etched with an image to be transferred on to the silicone pad
and then to the part. |
| Clogging |
Premature
drying of ink in the screen, causing bad print by blocking part
of the open stencil. |
| CMC
(Colour Measurement Committee) |
Of
the Society of Dyes and Colourists in Great Britain. Developed a
more logical, ellipse-based equation for computing DE values as
an alternative to the rectangular co-ordinates of the CIE LAB colour
space. |
| CMS
(Colour Management System) |
A
system to measure and control the process colours that are used
in four-colour printed reproduction. See Colour Management System. |
| CMY
(Cyan, Magenta, Yellow) |
Three
subtractive primary colours used in colour-negative printing, and
some colour-output devices, to produce a full gamut of colour. The
combination of pure CMY inks produces black, and the elimination
of all three produces white. |
| CMYK |
Cyan,
Magenta, Yellow, and Black (or Key) are the four colours used in
process-colour printing. Also known as subtractive colour, the colour
black is achieved by the presence of all inks. |
| Coated
Paper Stock |
A printing paper having a transparent, smooth layer added to one
or both sides that changes the look of the final printing. Coatings
are normally defined as hard glossy, semi-glossy or matte surfaces. |
| Cobwebbing |
Fine
filaments produced by the ink between the pad and the substrate
being printed, culminating in a cobweb-like appearance on the finished
print. It may be reduced to a minimum by careful selection of solvents
and proper adjustment of printing conditions, and reduction of static
charge. |
| Cohesion |
The
forces which bind the particles of ink or varnish film together.
It is distinct from "adhesion", the forces binding the
film to its substrate. |
| Cold
Curing |
The
process of curing at normal atmospheric temperature. |
| Colour
|
1)
The subjective appearance of the printed ink. Note that this definition
embraces all colours and black and white. 2) Synonym for ink. |
| Colour
Attribute |
A
three-dimensional characteristic of the appearance of an object.
One dimension usually defines the lightness, the other two together
define the chromaticity. |
| Colour
Bar (or Production Control Bar) |
A
series of ink patches printed on a press sheet that may include
solids of cyan, magenta, yellow, black, and spot colour ink; 25%,
50%, and 75% tints of those colours; and two-colour overprints using
those colours. |
| Colour
Calibration |
A
system of software and/or hardware that adjusts and co-ordinates
colours between two or more digital devices. Colour calibration
systems commonly compare device colour profiles and translate one
colour model into a device-independent language. |
| Colour
Compression |
Shrinking
the colour gamut of the original to the colour gamut a printing
process will represent. |
| Colour
Curve |
A
graphic mechanism for displaying colour measurements and for making
colour changes to an image. User adjustments to the angle and slope
of the curve implement colour changes to one or all of an images
colour channels. |
| Colour
Difference |
Magnitude
and character of the difference between two colours under specified
conditions. |
| Colour
Gamut |
A
range of colours that can be reproduced by a given system. |
| Colour
Management System (CMS) |
A
combination of software and or hardware devices used to produce
accurate colour results throughout a digital-imaging system. |
| Colour
Match |
Inks
are said to match in colour if, under specified conditions of illumination
and viewing, no significant difference in their hue, saturation
and lightness can be detected. |
| Colour
Matching Functions |
Relative amounts of three additive primaries required to match each
wavelength of light. The term is generally used to refer to the
CIE Standard Observer colour matching functions.
|
| Colour
Model |
A
colour measurement scale or system that numerically specifies the
perceived attributes of colour. |
| Colour
Proof |
A
colour sample that attempts to represent the final printed image
that will result when a piece is offset printed. Colour proofs can
be generated from film separations prior to using the separations
to make printing plates. Common types are Cromalin, MatchPrint,
ink jet, dye sublimation, laser copies, or photographic film or
paper. |
| Colour
Retention |
Colour stability after exposure to the elements. |
| Colour
Saturation |
Colour
Strength. A measure of colour purity or dilution by a neutral. |
| Colour
Separation |
The
process of separating a colour image into four subtractive colours,
CMYK, either by photographic or electronic processes, thus producing
a set of four films or a computer file. |
| Colour
Space |
Three-dimensional
mathematical model enclosing all possible colours. The dimensions
may be described in various geometries giving rise to various spacings. |
| Colour
Specification |
Tristimulus
values, chromaticity co-ordinates and luminance value, or other
colour-scale values, used to designate a colour numerically in a
specified colour system. |
| Colour
System |
A concept that relates colours for description or reproduction.
Models in imaging include CIE, PMS and Photo YCC, among others. |
| Colour
Temperature |
The
colour spectrum of a "black body" radiator heated to a
given temperature on the Kelvin scale. The manufacturer's method
of indicating the colour of a light source in degrees Kelvin (K);
i.e. 2700K (yellow/white), 4100K (white), 5500K (blue/white). |
| Colour
Transparency |
A
photographic or line-art image printed in colour on clear film.
A film positive. |
| Colour
Wheel |
The
visible spectrums continuum of colours arranged into a circle, where
complementary colours such as red and cyan are located directly
across from each other. |
| Colourants |
Materials
used to create colours-dyes, pigments, toners, and waxes. |
| Colourimeter |
A
device for measuring colour values; an optical measurement instrument
that responds to colour in a manner similar to the human eye by
filtering reflected light into its dominant regions of red, green,
and blue. |
| Colourimetric |
Of,
or relating to, values giving the amounts of three coloured lights
or receptors-red, green, and blue. |
| Colour-In
Film |
See
pigmented. |
| Colour-Matching
Functions |
The
mathematical relationships that assign a weight to red, green, and
blue colour separations to reproduce the original colour. 3-by-3
matrixing is the use of a colour-matching function available on
some scanners. See also 3-by-3 matrixing. |
| Combustible
Liquid |
Liquid
having a flash point at or above 100 degrees Fahrenheit (37.8 degrees
C) but less than 200 degrees Fahrenheit (93.3 degrees C). |
| Compatible |
Two
or more inks or varnishes which can be mixed without producing any
undesirable effects, such as precipitation, belling, coagulation,
are said to be compatible. |
| Complementary
Colours |
Two
colours that, when combined, create neutral grey. On a colour wheel
complements are directly opposite the axis from each other; blue/yellow,
red/green, and so on. |
| Computer
Aided Design (CAD) or Graphics (CAG) |
System
used to generate and reproduce full-colour designs, artwork, photographs,
etc., through use of a computer, plotter, printer, etc. |
| Computer
Aided Manufacturing (CAM) |
Generally
describes any programmable, computerised, motor-driven system of
components that functions in a manufacturing capacity. |
| Consistency |
The
apparent viscosity of an ink or varnish when shearing forces of
varying degrees are applied to it in various ways, e.g. when it
is disturbed in the can, poured from one vessel into another, or
printed. |
| Conspicuity |
A
highly reflective film rendered in bright safety colours to enhance
appearance under highway conditions. |
| Continuous
Tone |
A
photographic image containing gradient tones. For printing purposes,
continuous-tone images are converted to dot patterns (halftones). |
| Contrast |
The
difference between the dark and light areas of an image. The lower
the number value, the more closely the shades will resemble each
other. The higher the number, the more the shades will stand out
from each other. Speed of density change; graduation. |
| Conversion |
In
computer imaging, to change a CMYK file to RGB, Photo YCC, or vice
versa, or to convert one file format to another. |
| Copolymer |
A
polymer of two or more different monomers. |
| Corona
Discharge |
An
electrical surface treatment that encourages oxidation through ionisation
of a surface to reduce surface tension and improve ink adhesion. |
| Coverage |
The
area covered by one unit weight or unit volume of thinned ink under
defined printing conditions. |
| Cracking |
Specifically,
a breakdown in which the cracks penetrate at least one coat and
which may be expected to result ultimately in complete failure. |
| Cratering |
Undesirable
depressions in the dried ink film that may be large enough to expose
the substrate. |
| Crawling |
The
cohesive effect of ink into drops after printing onto a surface
which the ink does not wet completely. |
| Crazing |
A
"spider-web" cracking of paints or plastic, caused by
weathering, cleaning with strong solvents, or the use of improper
paints. |
| Creeping |
The
spontaneous spreading of liquid on the surface. In the case of an
applied film of ink or varnish, it refers to the spread of the wet
film beyond the area on which it was applied. |
| Crocking |
Image
rub-off that occurs when a pigment or dye is not adequately fixed
in the substrate. |
| Crop |
To
remove part of an image. |
| Curing |
The
process of condensation of polymerisation of a material by heat
or chemical means, resulting in the full development of intended
properties. |
| Curing
Agent |
An
addition which promotes the curing of a film. |
| Cutting
Plotter |
A
vector-driven device (similar to CAS plotters) for cutting sign-making
substrates. Recent designs include digital-print (inkjet) systems
combined with cutting-plotter systems. (See also, Plotter and Printer/cutter.) |
| Cyan |
One
of the three subtractive primary colours. Produced by mixing equal
amounts of blue and green projected light. Cyan is also one of the
four colours used in four-colour printing. |
