| Lacquer |
Fast-drying
clear coating with plastic, film-former base. |
| Laminate |
To
apply film to a surface by hand or by mechanical applicators. A
web or sheet material formed by bonding materials together. |
| Lamination |
Bonding
one product to another by pressure for protection or appearance. |
| Lamp |
Incandescent,
fluorescent tubes or high intensity discharge light sources. |
| Lay |
A
fixed point for positioning substrate on a print bed. |
| Lay
(False) |
A
temporary positioning point on a print bed, applied by the printer. |
| Lay
Flat |
Release
liner that does not change when exposed to changes in humidity. |
| Lead-Free
Ink |
Inks
for special purposes where the presence of lead constitutes a danger,
e.g. in food packing. |
| Letter
Press |
Printing
from a plate having a raised inked surface. |
| Levelling |
See
"Flow". |
| Lift
Off |
Pad
movement off plate and product. Also sometimes used as a description
of snap off in screen printing. |
| Light |
Electromagnetic
radiation of which a human observer is aware through the visual
sensations that arise from the stimulation of the retina of the
eye. The portion of the electromagnetic spectrum that the human
eye can see. |
| Light
Fast |
The
description of an ink, pigment or dyestuff which retains its original
colour on exposure to light under defined conditions. |
| Light
Source |
An
object that emits light or radiant energy to which the human eye
is sensitive. |
| Lightness |
Perception
by which white objects are distinguished from grey objects and light-
from dark-coloured objects. |
| Like
Differences |
Differences
in colour or lightness that are of similar magnitude to the average
observer. |
| Line
Art |
1)
Single colour diagrams or drawings; 2) An image that requires sharp
edges and high contrast between areas of the image that have ink
and those areas that do not have ink. These images require a higher
resolution to create the sharpness that is necessary. |
| Line
Drawing |
A
drawing that consists only of black and white with no intermediate
greyscale information. |
| Lithography |
A
method of printing from a plane surface. The printing image is ink-receptive;
the non-printing areas are ink repellent. |
| Low
Key |
A
photograph or other image whose tonal range is mostly in the shadow
regions. |
| LPI
(Lines Per Inch) |
The
number of lines per inch on a halftone screen. As a general rule,
the higher the l.p.i., the higher the printed resolution and quality. |
| LPM |
Abbreviation
for line pairs per millimetre. |
| Luminous |
An
ink, which exhibits fluorescence or phosphorescence. 1) Fluorescent
ink: contains pigments which are capable of absorbing energy from
the blue or ultra-violet end of the spectrum and re-emitting it
in the form of light in the visible wavelengths. A fluorescent ink
ceases to glow if the active source is removed. 2) Phosphorescent
ink: contains pigments (phosphors that absorb energy at one wavelength
and emit it over a wavelength in the visible spectrum. It differs
from a fluorescent ink in that it continues to glow for a time after
the stimulating source has been removed. |
| LUX,
Foot candles |
A
unit used to measure light falling on a surface (illuminance). LUX
x .0929 = Foot candles |
