Warm color
Color of ink falling in the red/orange/yellow family.

Wash-up
Operation between ink/color changes; time required between ink color changes.

Washing
A method of rinsing residue from recovered pulp after it has been deinked.

Water ball roller
A roller that runs in the fountain solution pan.

Water fountain
The metal trough on a lithographic press that holds the dampening solution.

Water in ink
A press condition of too much water, which breaks down ink.

Water resistance
Quality of a sheet of paper to resist penetration by water from one surface to the other.

Waterless plate
In platemaking, printing on a press using special waterless plates and no dampening system.

Waterless printing
A printing process that runs on offset lithography presses without the use of water. The non-image areas of the plate are coated with silicone so that ink can run off into shallow wells in the plate. Waterless printing supports finer dots and finely detailed images. This process is more expensive than traditional lithography.

Watermark
A term referring to the impression of a translucent 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 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.

The second type of watermark, called 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.

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 on each sheet in a predetermined fashion. (Also 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 then the outer edges do. It is a form of paper curl.

Web
Roll of paper used in web or rotary presses and most often folded, pasted and converted in one continuous form. Also a ribbon of paper as it unwinds from a roll and threads through the press.

Web break
A tear through a roll of paper, either at the paper mill or on press. Web breaks can cause costly down time in production.

Web paper
Designed for web presses, this paper comes in a roll rather than sheets and is folded and cut on press after it has been printed.

Web offset paper
Paper that is made to be printed in a continuous manner from a roll. It can be coated or uncoated and must be strong enough to withstand the rigors of web offset printing at high speeds.

Web press
An offset press that uses web paper as opposed to sheet-fed paper.

Web tension
Amount of pull applied in direction of the travel of a web of paper by the action of a web-fed press.

Weight
The tonnage or poundage of a quantity of paper. Paper weight may be expressed as basis weight, ream weight, M weight or grammage.

Weight tolerance
Acceptable degree of variation in a paper's shipped weight, usually within 5% of the paper's nominal weight.

Well-closed formation
Bonding of fibers in a sheet that provides an overall uniformity.

Wet end
The start of the papermaking process, where the pulp slurry is poured from the headbox onto the forming wire and wound through presses to remove water from the sheet.

Wet-end finish
Category of finishes such as antique, eggshell or vellum; applied to the wet paper web by machine rolls and the presses at the wet end of the papermaking machine.

Wet rub test
A test of the moisture resistance of paper.

Wet strength
The strength retained by a sheet when completely wetted with water. Also, generally, tensile strength. Wet strength is measured most accurately as the percentage ratio of wet-tensile strength to dry-tensile strength. Example: a paper containing 30% wet strength actually possesses 30% of its original dry-tensile strength.

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 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 dry strength following immersing in water. Wet strength papers range in weight from tissue to paperboard.

Wet trap
Printing a layer of wet ink over or adjacent to a previous layer of wet ink.

Wetting agent
A material capable of lowering the surface tension of water and water solutions, while increasing their wetting powers.

White paper
A term often applied to printing and writing grade papers and envelopes.

Whiteness
A measure of the amount of light reflected from a sheet of paper. Whiteness of pulp and paper is generally indicated by its brightness. Paper that reflects more blue than red or yellow will have a cool, blue tinge and appear to be a brighter white than a warm-tinged sheet. The color white is defined in colorimetric terms as a color with the highest luminosity, no hue and no saturation

Wicking
The tendency for a liquid, such as ink, to feather or move on the surface of a sheet of paper or through the paper to the other side.

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.

Window (envelopes)
A cut-out in the body of the envelope positioned to show mailing address, return address and/or special messages. Customized windows can be created in the shape of a product or logo. Can be left open with no patch, except in Canada.

Window position (envelopes)
Location of the window on the envelope, as measured from the left and bottom edges of the envelope. Window edge should be no closer than 3/8" from the side (to allow space for gluing window material) and 5/8" from the bottom (to correspond to current postal recommendations) of a standard commercial envelope.

Wire
At the wet end of the paper machine, a copper, bronze or synthetic screen that receives the suspension of water and fiber from the headbox. The wire moves the suspension along to the dry end of the machine. The wire terminates at the couch roll, at which point the paper web is 90% water and can be transferred to the wet felt. In business forms, to stitch or fasten sheets to form a book or fastened set; may be side or saddle wired.

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 bottom side of the paper that comes in contact with the forming wire of the papermaking machine. Opposite of felt side. There can be a slight texture difference between the wire and felt sides. A watermark will read backward from this side of the sheet.

With the grain
Parallel to the direction in which the paper fibers lie.

Wood-free pulp
Chemical pulp.

Work-and-back
The method of printing each sheet first on one side with one form, then on the other side with another form. This is also known as sheetwise.

Work-and-tumble
The method of printing a sheet with the same pages on the front and back, using the same side guide and plate to print the second side. After the first run, the sheet is tumbled bottom-to-top and printed on the second side. When cut and folded, the sheet yields two or more finished pieces.

Work-and-turn
To print one side of a sheet of paper and then turn the sheet over from left to right after the first run so the same material can be printed on 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 without a watermarked design.

Wove finish
Originally made with a finely woven wire screen to eliminate rib lines, today a wove surface is imparted using wet felts. Wove papers are valued for their cloth-like texture and smooth, even-sided finish.

Wrinkles
(1) Creases in paper occurring during printing or folding. (2) In inks, the uneven surface formed during drying.

Writing grades
Papers that are typically used for business letterhead and personal stationery.

Writing paper
A general term applied to papers used for writing purposes.

Wrong-read image
A mirror image such as that appearing on the blanket in offset printing.