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 North America's #1 Resource for Paper Grade and Company InformationFriday, March 29, 2024  
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Walden's Paper Catalog Glossary of Terms:
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warping
Wavy-edged defect in binder board where edges of sheet have expanded more than in the center.
wash up
In reference to printing, operation between ink/color changes. Time required between ink color changes.
wastepaper stock
Pulp derived from paper that has been recycled.
water finish
Water finish which resembles the machine glazed finish, is obtained by moistening the web with a fine spray of water or steam as it passes through the calender stacks of the paper machine. Moisture thus applied softens the web of paper permitting it to be calendered to a glossy finish. Water finish is applied to tag and paperboard.
water resistance
Quality of a sheet of paper that enables it to resist penetration by water from one surface to the other.
water silk finish
Embossed finish simulating water-finished silk.
waterlined paper
A writing paper with watermarked lines running through the sheet.
watermark
A term referring to the impression of a design, pattern or symbol in a sheet while it is being formed on the paper machine wire. It appears in the finished sheet as either a lighter or darker area than the rest of the paper. Two types of watermarks are available. A wire mark, is accomplished by impressing a dandy roll with a raised surface pattern into the moving paper web in a similar manner to the shaded mark. This creates an area with less fiber making it lighter and more translucent. A shaded watermark is produced by a dandy roll located at or near the suction box on the Fourdrinier. The desired design is pressed into the wire covering the surface of the dandy roll similar to an intaglio engraving. As the wet pulp moves along the web the dandy roll presses down and creates an accumulation of fibers, thus the watermark is seen as being darker than the rest of the sheet. Placement: Watermarks come in a variety of placement styles. Random, the least expensive to create, is a watermark that appears repetitively throughout the sheet in no particular order. A localized watermark is one that appears in a predetermined position on each sheet. Paraded watermarks appear in a line, either vertically or horizontally on each sheet. A staggered watermark pattern consists of several watermarks appearing on each sheet in a predetermined fashion (See dandy roll).
waviness
Characteristic of a pile of sheets when the outer edges retain more moisture from the air than the center does or when the center retains more moisture than the outer edges do. It is a form of paper curl.
wax pick
A test to determine the surface strength of paper or board, see Chapter 6.
web
Roll of paper used in web or rotary printing presses. Also a ribbon of paper as it unwinds from a roll and threads through the press.
web break
Break in a roll of paper while it is on the machine during manufacturing or while on the printing press during production.
web cleaner
Vacuum cleaner situated in advance of the first printing unit to remove foreign particles from the web.
web direction
Direction parallel with the long dimension of a mill roll.
web lead
Amount of paper in the press when threaded.
web offset paper
Paper that is made to be printed in a continuous manner from a roll. Strong enough to withstand the rigors of printing at high speeds.
web press
Printing press that prints from rolls of paper.
web tension
Amount of pull applied in the direction of the travel of a web of paper by the action of a web-fed press.
web tension meter
Hand-held instrument the size of a pistol. Used to compare tension on right and left edges of the web of paper.
weddings
Superior quality, vellum finished, writing papers.
weft wire
Fourdrinier wire.
weight tolerance
Very generally, mills make and ship paper to a tolerance in weight within a specified percentage of the nominal weight.
well-closed formation
Bonding of fibers in a sheet that provides an overall uniformity.
wet end
Beginning of the paper machine where the headbox, moving wire and press section are located. At this point the paper is still a suspension of fiber and water.
wet refining
Method of treating fibers in which wood waste or completely cooked wood is disintegrated in water to form a pulp.
wet rub
Resistance of wet paper to scuffing and linting.
wet-and-dry-bulb Hygrometer
A hygrometer of two matched thermometers, one having a wick surrounding its bulb to be moistened with water prior to taking a reading. Relative humidity is read from a table of dry-bulb temperatures and wet-bulb depressions.
wet-end finish
Category of finishes such as antique, eggshell, vellum applied to the wet paper web by machine rolls and the presses at the wet end of the papermaking machine.
wet-machine
A cylinder type papermaking machine used to make certain types of board, and also to achieve partial drying of pulp to permit folding into laps.
wet-strength papers
Once wet, ordinary papers lose most of their original dry-strength properties. Wet strength papers possess properties that resist disintegration and rupture when saturated with water. Papers are usually classified wet strength when they retain 15% or more of their dry-tensile strength. Superior quality wet strength papers may retain as much as 50% or more of their dry strength following immersing in water.
white papers
A term that is used by some persons to refer to printing and writing papers.
whiteness
So-called white papers have a definite hue. Most are made with a blue-white tint. Whiteness of pulp and paper is generally indicated by its brightness which is reflectance of a wave length of blue light.
whitewater
Water that has been used in the papermaking process and separated from the stock or pulp suspension. It is milky in color.
wholesaler
(See distributor).
wild
In reference to paper characteristics, irregular formation of fibers in a sheet. Opposite is well-closed or close.
winder
Unit at the end of the paper machine that takes the paper web from the reel, trims it, winds it into rolls and slits it to make smaller rolls if desired.
wire
In reference to paper manufacture, an endless belt woven from plastic or metal for use on a Fourdrinier paper machine that receives the suspension of water and fiber from the head-box. The wire moves the suspension along to the dry end of the machine.
wire binding
A continuous double series of wire loops running through punched slots along the binding side of a booklet.
wire mark
On the bottom or wire side of the paper, these are impressed traces of the machine wire.
wire side
The side of the paper that was against the wire during manufacture.
woodfree pulp
Pulp that is free from mechanical pulp, i.e. free from lignin.
work and tumble form
To print one side of a sheet of paper then turn the sheet over from gripper to back, using the same side guide and plate to print the other side of the paper.
work and turn form
To print one side of a sheet of paper then turn the sheet over from left to right and print the second side. The same gripper and plate are used for both sides.
wove
Finish characterized by the impressions of a felt dandy roll covered in woven wire and without laid lines.
wove dandy
A dandy roll covered with a wire cloth to permit the production of a wove finish.
wrap-around plate
Usually refers to a flexible plate used for rotary letterpress printing.
write-through
Process of transferring an image beyond the original, through the several parts of a set.
wrong-read image
A mirror image such as that appearing on the blanket in offset printing.
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