 |
| Or select from the general listing below: |
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
|
Shown below are the definitions for: P
 |
packing In printing presses, paper or other sheet materials used to underlay the plate and/ or blanket (between the cylinder and plate or blanket), to bring the surface of the plate or blanket to the desired height to obtain proper squeeze pressure for printing: can also be adjusted to compensate for minor dimensional changes in the paper in multipass, multicolor printing jobs, but only around the circumference of the cylinder (the print length).
|
padding compound Also called edge padding glue or adhesive; A liquid adhesive mixture which when brushed or sprayed onto the side of a pile of paper adheres the sheets together along one edge, thus forming a pad.
|
paper machine The machine upon which paper is produced from a suspension of cellulose fibers and other components in water (the furnish) by forming, pressing, drying, surface sizing (in some cases), calendering, and winding on a reel.
|
paper master See "paper plates".
|
paper plates A plate for an offset duplicating printing press (offset lithography) made of paper: can be called a "paper master" or "master".
|
paper A relatively homogeneous matting of primarily cellulose fibers which are formed from a water suspension on the paper machine wire and bound together by entanglement of the fibers and by bonding agents, and subsequently dried.
|
papeterie A wide variety of writing papers. used for personal correspondence and greeting cards, with good sizing for pen and ink, with good opacity arid stiffness, and that fold well.
|
parchment Originally a writing surface made from animal skins; today made from cellulose fiber paper by dipping unsized stock in sulfuric acid, to simulate the appearance and feel of genuine parchment; called "vegetable parchment" if made from cellulose fiber paper.
|
paste-up Assembled on one page for photographing the various art, display and text copy for a printing job; another term used is "mechanical".
|
paste dryer/drier In ink making, a type of dryer used in inks, usually a combination of dryer compounds; see "dryers".
|
paster See "splice".
|
perfect binding A Process of holding pages of a book together with glue (like padding), using no stitching or sewing. The backbones of the books are usually roughened, the adhesive applied, -and finished with a wrap around cover
|
perfect/perfecting press The terms apply to printing both sides of the paper in the same pass on the printing press. Also to print on the back of a sheet already printed on one side. Printing can be on opposite sides, either blanket-to-blanket or sequentially.
|
perforate Punching a series of holes or slits in a line in the paper, to weaken it so tearing will occur easily along that line. Also the making of slits in paper during folding, at the fold, to prevent wrinkles and to allow air to escape.
|
perfs The actual holes or slots created during perforating.
|
permanence The resistance to paper to the destructive effects of age; also the "archival" properties of the paper or printed job. A lack of permanence is indicated by a significant loss in strength of the paper or a fade in the color or shades of the paper or printed image. The permanence of paper is chiefly dependent upon the purity of the cellulose used to make the paper, the acidity (see pH) in the paper as a result of manufacture or later contact, and the storage of the paper away from heat, light, and moisture.
|
personal computer An electronic device, programmable to carry out a variety of functions, and intended primarily for use by one operator at a time.
|
photoconductor See "photoreceptor".
|
photoreceptor See "electrostatic copier/ printer"; the surface or plate in an electrostatic/ xerographic copier or printer where the image and non-image areas are distinguished. The characteristic of a photoreceptor material is that it holds an electrostatic charge on its surface in the dark, and until the charge is dissipated or erased by exposure to light; when a material has this property with respect to electrostatic charges and light, it is known as a photoconductor.
|
pH A scientific scale from 0 to 14, measured by instruments, and defining the strength of an acid or alkaline (basic) liquid. From 0 to 7 is acid-, from 7 to 14 is alkaline, while 7 is considered "neutral". i.e., neither acid or alkaline.
|
pica See "point" (2).
|
picking The lifting of any material off of, or out of, the paper surface during the printing impression; sometimes due to surface contamination, inadequate surface sizing, inadequate surface strength, or to the ink being too tacky. Generally, the pick will adhere to the blanket and interfere with future impressions;, can appear to be hickeys in the printed surface. For measurement of picking see "I.G.T." and "wax pick".
|
pigment 1) Minerals and other materials used in the manufacture and coating of paper, to provide desired properties. 2) Minerals and other materials, ing colorants, used in the manufacture of printing inks; finely divided solid materials.
|
piling The collecting of ink particles upon rollers, blankets and plates, caused either by the inability of an ink vehicle to hold the ink pigment in suspension, or by microscopic pick and/or removal of pigment from the surface of the paper by the ink, and accumulating in the ink on the blanket, usually evidenced in the trailing edge of the image areas, resulting from extra thickness on the press blanket in the image area. If "milking" or "whitening" is severe enough, an accumulation of foreign material can occur in the nonimage areas, also creating an extra thickness there; this is also called non- image area "piling".
|
pinholes Imperfections in paper which appear as minute holes upon looking through the sheet: accentuated by lower basis weights.
|
planographic printing See "offset lithography".
|
plate cylinder The cylinder on the printing press around which the plate is mounted.
|
plate gap See "cylinder gap".
|
plate Depending on the printing process, the means by which the image area is separated from the non-image area; the image carrier.
|
plybond Internal bond strength, measure of the resistance of a sheet of paper to delaminate or blister, due to stresses created during printing and drying.
|
PMS color An abbreviation for "Pantone Matching System"; an ink color system containing about 500 color swatches, each of which is identified by a color number and a formula for the ink.
|
point 1) See caliper; refers to the thickness of a sheet of paper in one thousands of an inch. 2) A unit of printing type measurement; 0.0 138 of an inch- 12 points to the pica-each pica being about 1/6th of an inch, or 72 points to the inch.
|
poor splice See "splice".
|
poor start Also called bad start; is when there is an obvious difference in the mechanical appearance between paper near the core and the remainder of the side of the roll.
|
porosity A test which measures the time required for a given amount of air to flow through a sheet of paper; defines how open or tight the sheet of paper is with respect to the passage of air through the sheet.
|
porous printing See "screen printing" and "mimeograph printing".
|
portrait mode A printer (usually driven by a computer) output orientation in which the printed lines run perpendicular to the direction of movement of paper; see "landscape mode".
|
pre-collated See "collated"; sheet papers purchased in a predetermined sequence, generally for the sheet printing of business forms.
|
press run The quantity specified for any given printing job. Also, the number of impressions made from a printing plate.
|
press section See "wet press".
|
primary colors The additive primary colors are the three major wavelengths of light in the visible spectrum: red, green and blue, and are used in applications such as the cathode ray tube of a color television set. The subtractive primary colors are used when dealing with reflected light, such as from a full color printed piece, and are yellow, magenta, and cyan. These are the three colors of ink used in process printing. In paper making, red, yellow, and blue are the primary colors in the dyeing of paper, any two of which can be mixed together to obtain secondary colors and hues (green, orange, and violet).
|
print contrast A differential measurement of light reflectance between the image and background areas.
|
printing inks Special coatings applied over specific areas of the paper surface by means of a printing press.
|
printing The act of producing an image on a page from a machine designed for that purpose, such as a printing press or a computer printer like a laser or ink jet.
|
process inks/colors Transparent inks used in three-color and four-color printing of full color pictures or drawings; subtractive primary ink colors are yellow, magenta, and cyan; see "three and four-color process".
|
process printing The printing from two or more halftone plates, to produce intermediate shades, hues, and tonal values-, see "three and four-color process".
|
proofs Samples of copy and/or layout made at various stages of production of a printing job.
|
psychrometer An instrument for determining the relative humidity of an atmosphere.
|
puffing See "fiber puffing".
|
pulping The act of processing wood (or other plant) to obtain the primary raw material for making paper, usually cellulose fiber. Wood is the most widely used source of fibers for the paper making process. Chemical pulping is generally of the "Kraft" or Sulfate process, the Soda process, or the Sulfite process-see each. Wood pulp can also be obtained for paper making by purely mechanical means ("groundwood") or in combination with chemicals or at elevated temperatures (see "semi-chemical and thermomechanical" pulps); also see "refiner mechanical pulp (RMP)".
|