| Anilox
Roll |
Mechanically or laser-engraved roll for transfer of ink to printing
plate. Specifications are in lines per inch and cell volume
(ex. 800-line anilox will transfer a thinner film of ink than
a 300-line anilox). |
| Bleed |
An extra amount of printed image which extends beyond the trim.
Typically bleed is 1/16 inch for pressure sensitive die cut
labels. |
| Blocking |
Substrate sticking to itself after being printed and rewound.
Image often transfers to back-side of other label. |
| Caliper |
The thickness of the substrate usually measured in thousandths
of an inch (mils). "Microns" (metric) are specified for some
substrates. |
| Cell
Count |
The number of cells per inch on an anilox roll. |
| Cell
Volume |
The amount of ink an anilox cell can hold specified or measured
in billions of cubic microns (bem). |
CMYK
Color
Model |
A color model based upon the subtractive primaries cyan, magenta,
yellow and black. New colors are formed by combining cmyk in
varying reflectance intensities (commonly referred to as 4-color
process). Black is used to provide increased darkness. |
Coefficient
of Friction
(COF) |
The ratio of frictional force resisting movement of the surface
being tested to the force applied normal to that surface. Measured
as static (from a dead stop) and kinetic (moving across the
surface). |
Color
Correction |
Any method such as masking, dot etching, re-etching and scanning,
used to improve color rendition. |
Computer
to
Plate (CPT)
System |
System designed to image printing plated directly from computer
data therefore eliminating the need for film production and
the use of contact plates. |
| Curl |
"Upturn" (face) or "downturn" (backside) condition existing
when printed matter is held in a vertical position. Curl may
be TD (transverse direction) or MD (machine direction). |
| Density |
The degree of darkness (light absorption or opacity) of a photographic
or printed image. |
| Diecutting |
A finishing operation whereby some geometric shape is cut from
the printed piece by pressing it against a flat, curved or cylindrical
surface with cutting and creasing edges (done in-line at ROI). |
Digital
Proofing |
Using a computer output device to create a facsimile image of
how the printed piece will appear after printing. |
Doctor
Blade |
Thin, flexible steel, plastic or composite blade that passes
over a gravure plate cylinder or flexographic anilox roll wiping
off excess ink before ink is transferred to substrate or plate. |
| Dot
Gain |
The change in apparent size of printing dot from the film/plate
to the substrate. Also referred to as tone value increase. |
Dots
per
Inch (dpi) |
A measure of the resolution of a screen image. ROI recommends
printing high quality digital images at no less that 300 dpi. |
Fine
Printing |
Flexography
is the latest fine printing process. It rivals and can sometimes
exceed the quality of lithography. |
| Flexography |
A form of rotary web letterpress using flexible rubber or photopolymer
plates and fast-drying solvent, water-based or UV inks. Photopolymer
plates with raised surfaces that transfer ink to the substrate
are mounted to print cylinders using double faced adhesive (stickyback). |
Grain
Direction |
The
alignment of cellulose fibers in a paper or paperboard substrate. |
| Halftones |
A printed image of a continuous-tone original (like a photograph)
that is composed of tiny dots to create the illusion of continuous-tone
though printed with only single density. Halftones are reproduced
in screen values for flexographic printing from 80 line (carton,
fiber board and course papers) to 300 line (high gloss, smooth
finish papers). The majority of high quality flexographic printing
uses 133 to 150 lines screened halftones. |
| Lithography |
(Also Offset) A printing process whereby image transfer is accomplished
through the use of plates with a flat surface. Where image areas
accept ink, non-image areas accept a water/alcohol solution
that repels ink. The ink is then transferred to a rubber blanket
and subsequently to the substrate. |
| Nip |
Line of contact between two rollers. |
| Overs/Unders |
Copies printed varying from the specified quantity. Depending
on the quantity ordered, the standard in our industry is usually
10%, unless otherwise specified. |
| OTR |
Term used in pouching material - Odor Transmission Rate. How
fast the odor will pass through the substrate. |
| Plate
Gap |
The space left when the plates are wrapped around the cylinder.
No copy or image can be printed in this area that is usually
1/8" wide. |
Plate
Cylinder |
The cylinder of a press on which the plate is mounted. |
| Prepress |
A general phase of production that includes all operations taking
place before presswork (like design, scanning, page layout and
platemaking). |
| Process
Color |
The use of cyan, magenta, yellow and black halftone images to
create full-color printed reproductions. |
| Proof
|
A facsimile image of the final printed piece created before
presswork begins. Used for evaluation by production staff and
customer prior to printing. |
| Register |
The fitting of two or more images on top of each other in exact
alignment. |
| Rewinding |
The process of rewinding a roll of substrate to produce a proper
size for the customer, to splice the ends together and/or to
remove defects. |
| Rotogravure |
The printing process that involves the principal of engraving.
An engraved cylinder is immersed in a fluid ink; the ink is
wiped or doctored from the surface of the cylinder; and the
ink left in the recessed area of the cylinder is transferred
to the substrate. |
Screen
Printing |
A printing process that employs stencils adhered to tightly
drawn screens in flat or cylindrical configurations. Ink is
forced through the openings in the stencil and onto the substrate.
This process is well suited for printing materials like glass,
wood, thick plastics and textiles; or where heavy coverage of
ink is required to create desired opacity. |
| Slitting |
Cutting printed sheets or webs into two or more sections by
means of cutting wheels on a press or rewinder. |
| Solvent
|
Liquid that dissolves a solid. In ink, the evaporation of solvent
leaves the solids behind as an ink film on the substrate. |
| Stochastic |
A halftone screen where the dots are of unequal size and tones
created by varying the concentration of dots. |
| Substrate |
Any printing surface (paper, polypropylene, polyester, PVC,
PETG, etc.). |
| Trapping |
The creating of slight overlap between background and foreground
colors to compensate for technical limitations of the printing
process. Lithography (offset) will hold .004" while flexography
should have art prepared for a minimum of .010". |
| Viscosity |
The property of an ink defined as the resistance to flow or
simply the fluidity or thickness of the ink. |
| WVTR
|
Term used in pouching material - Water Vapor Transmission Rate.
How fast moisture passes through the substrate. |
