Glossary / L

Label papers
Mostly one–side coated papers which must be printable in 4–colour offset and gravure printing. These papers are usually suitable for varnishing, bronzing and punching and sometimes also feature wet strength and alkali resistance (See "Wet strength and alkali resistant paper") in order to ensure the removal of the labels e.g. in the bottle rinsing machines of breweries.

Lacquering
Application of lacquer to give paper greater gloss and stiffness (brochures and some magazine covers).

Lightweight coating
Coating applied at 7–10 g/m² on one or both sides of the paper.

Light–weight printing paper
Light–weight paper has a low grammage and is made from rags and bleached kraft pulp and is used e. g. for advertising material (catalogues, leaflets, mailings etc.), commercial and/or jobbing work (magazines, brochures, instruction leaflets, forms etc.).

Lignin
Natural "adhesive" which binds wood fibres together in the tree and imparts rigidity. Pulp brightness depends on the amount of lignin remaining in the pulp. Paper containing high content will "yellow" in sunlight.

Laminated paper
Paper (card, board) composed of several, joined layers. They can be joined when or whit adhesive when dry. For the same grammage, dry lamination is stiffer than wet. Lamination can be undertaken during paper manufacture or during conversion, when a printed sheet is laminated to a card, board or other material.

Laser printing
The computer sends the page data to a RIP, which separates the colours and screens the images (54–60 lines). The printing cylinder is electrostatically charged and imaged with the page data during is rotation. The sensitised cylinder is inked and transfers the image to a rubber cylinder and from this to the printing substrate by means of the pressure of the third cylinder.

Lime kiln
Used to reburn lime sludge (CaCO3) to form calcium oxide (CaO), which can be reused.

Lime sludge
Sludge of calcium carbonate (CaCO3) formed during preparation of white liquor in the chemical pulping process.

Linen finish
Imitation linen texture impressed onto the paper surface.

LWC
Light weight coated paper intended for rotogravure or web offset printing, with a low grammage (35–70 gsm) and a base containing mechanical pulp. The most common grades are gloss but there are also matt LWC papers characterised by a velvety, non–reflective surface. These papers are most commonly used for the printing of magazines, catalogues, and commercial printings.