| Abrasion
Resistance |
Resistance
to frictional rubbing as distinct from resistance to knocks and
impacts. Abrasion tests may be made by means of the finger alone,
or with a cloth or a pad with or without a mildly abrasive powder.
The pressure, speed and time of rubbing as well as the character
of the rubbing agent should be controlled when making comparisons
of abrasion resistance. |
| ABS |
Acrylonitrile-butadiene-styrene,
a thermoplastic. Hs good impact resistance and a surface that is
easily decorated. |
| Absolute
White |
In
theory, a material that perfectly reflects all light energy at every
visible wavelength. In practice, a solid white with known spectral
data used as the "reference white" for all measurements
of absolute reflectance. |
| Accelerator |
A
solvent, or other material, which is added to an ink in order to
increase its drying rate, i.e.. to make it dry quicker. |
| Acetate |
Cellulose
based thermoplastic |
| Achromatic
Colour |
Neutral
colour & white, grey, or black & that has no hue. |
| Acrylic |
A
thermoplastic. A common one is known commercially as "Perspex" |
| Acrylic
Adhesive |
An
adhesive made of acrylic polymers. |
| Acrylic
Ink |
Ink
with an acrylic component. |
| Actinic
light |
Actinic
light is a light that causes a chemical reaction to take place.
Ultra violet light is an example. |
| Additive
Colours |
The
three additive primary colours are red, green and blue. When these
three colours of light are mixed in equal proportions, they will
produce white light. Also known as additive primaries. |
| Adhesion |
The
power of an ink to stick to the surface on which it was printed.
In general, measured by scratching off method, using a fingernail,
or a pull-off method using self-adhesive tape (Scotchtape test).
The measure of the strength by which two materials bond together. |
| Adhesion
Test |
Test
methods used to determine the adequacy of ink coating adhesion to
a substrate. A common test is the Cross-cut tape test. |
| Algorithm |
A
mathematical routine that solves a problem or equation. In imaging,
the term is usually used to describe the set of routines that make
up a compression or colour-management program. |
| Aliasing |
The
visual stair-stepping of edges (jagged edges) that occurs in an
image when the resolution is too low. Can be caused by improper
image sampling or improper image processing. |
| American
National Standards Institute (ANSI) |
The
official US standards organisation, the U.S. member of the International
Standards Organisation (ISO), responsible for industry standards. |
| Angel
Hair |
Undesirable
fine threads of ink caused when the ink pulls away from the printed
surface. (see cobwebbing) |
| Anti-Aliasing |
The
smoothing and removing of aliasing effects by electronic filtering
and other techniques, such as blending of hard edges. Also, blending
object-oriented art with bit-mapped art. |
| Apparent
Dot Area |
The
percentage of dot coverage in a specific area, as measured using
a densitometer. |
| Apparent
Dot Gain |
The
difference between the Apparent Dot Area of the film, as measured
by a transmission densitometer, and the Apparent Dot Area of the
proof or printed sheet, as measured with a reflection densitometer. |
| Aqueous |
(See
"Water Based"). |
| Artificial
Weathering/Accelerated Weathering |
Laboratory
test designed to simulate, but at the same time to intensify and
accelerate the destructive action of natural weathering on ink films.
The test involves exposure to artificially produced components of
natural weather, e.g. light, heat, cold, water vapour, rain, etc.
which are arranged and repeated in a given cycle. |
