Laid paper is a type of paper

Paper

Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

 having a ribbed texture imparted by the manufacturing process. In the 19th century its use diminished as it was largely supplanted by wove paper

Wove paper

Wove paper is a writing paper with a uniform surface, not ribbed or watermarked.The papermaking mould's wires run parallel to each other to produce laid paper, but they are woven together into a fine wire mesh for wove paper...

. Laid paper is still commonly used by artist

Artist

An artist is a person engaged in one or more of any of a broad spectrum of activities related to creating art, practicing the arts and/or demonstrating an art. The common usage in both everyday speech and academic discourse is a practitioner in the visual arts only...

s as a support for charcoal

Charcoal

Charcoal is the dark grey residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen...

 drawing

Drawing

Drawing is a form of visual art that makes use of any number of drawing instruments to mark a two-dimensional medium. Common instruments include graphite pencils, pen and ink, inked brushes, wax color pencils, crayons, charcoal, chalk, pastels, markers, styluses, and various metals .An artist who...

s.

In pre-mechanical papermaking (from the 12th century into the 19th century), the laid pattern was produced by the wire sieve

Sieve

A sieve, or sifter, separates wanted elements from unwanted material using a woven screen such as a mesh or net. However, in cooking, especially with flour, a sifter is used to aerate the substance, among other things. A strainer is a type of sieve typically used to separate a solid from a liquid...

 in the rectangular mold used to produce single sheets of paper. A worker would dip the mold into a vat containing diluted linen

Linen

Linen is a textile made from the fibers of the flax plant, Linum usitatissimum. Linen is labor-intensive to manufacture, but when it is made into garments, it is valued for its exceptional coolness and freshness in hot weather....

 pulp, then lift it out, tilt it to spread the pulp evenly over the sieve, and, as the water drained out between the wires, shake the mold to lock the fibers together. In the process, the pattern of the wires in the sieve was imparted to the sheet of paper.
Modern papermaking techniques use a dandy roll to create the laid pattern during the early stages of manufacture, in the same way as applying a paper watermark

Watermark

A watermark is a recognizable image or pattern in paper that appears as various shades of lightness/darkness when viewed by transmitted light , caused by thickness or density variations in the paper...

. While in the wet state, the paper stock (a dilute dispersion of the cellulose fibers in water) is drained on a wire mesh to de-water the stock. During this process, a dandy roll with a laid mesh pattern is pressed into the wet stock, displacing the cellulose fiber. This pattern has to be applied at a particular stock consistency; otherwise the pattern will be lost as the fiber flows back while the stock moves past the dandy (too wet), or fiber will pick out of the stock (too dry), causing surface disruption. As the fiber is displaced, localized areas of higher and lower density are produced in a laid pattern, and the pattern is also created on the paper's surface. The pattern is therefore apparent both as one looks through the sheet and as one views its surface. Applying the laid pattern as a mechanical emboss would not create the laid pattern effect on the look-through, as this is only achieved by watermarking techniques.

The traditional laid pattern consists of a series of wide-spaced lines (chain lines) parallel to the shorter sides of the sheet—or, in machine-made paper, running in the machine direction—and more narrowly spaced lines (laid lines) which are at 90 degrees to the chain lines.