The dandy roll is a hollow wire-covered roll that passes over the still wet paper on the web near the wet end of the papermaking machine. The dandy roll was invented by John Marshall (1826) as part of the papermaking machine. It was created to allow water in the paper to be removed, and to impress a watermark or laid impression into the still damp paper.
In traditional handmade papermaking the deckle was the wooden frame that held the papermaking screen.
In traditional handmade papermaking the deckle was the wooden frame that was held over the screen on which the pulp was placed and the water drawn through. The deckled edge of a sheet of paper is formed at the deckle and is generally thinner and irregular in shape. Hand made papers will have four deckled edges, and generally machine made papers will have two, although there are techniques by which a machine made paper can also have four deckled edges.
A process in which ink, fillers and sizing is removed from used paper that is going to be recycled into paper again. The recycled pulp after deinking can be added to virgin pulp or used alone to create a range of paper types. Justus Claproth developed a deinking process in 1774, and in 1801 Mathias Koop patented a deinking a paper recycling process. In the 1950s froth flotation deinking started to be used.
A chemical process in which lignin is removed from paper pulp leaving cellulose and hemicellulose. The sulfate, sulfite and soda processes are all methods to delignify wood to turn it into pulp.
The weight of a paper of a particular size. In the USA it is expressed as the Basis weight, and in the rest of the world as grams per square metre, which is written as g/m2 or gsm.
An amorphous silica that is used as a dulling or flattening agent in coating and a filler in paper. It is also known as diatomaceous silica, diatomite, infusorial earth and kieselguhr.
A machine that is used to defibrillate pulp. It consists of ribbed or serrated discs that are rotating and static, or rotating counter to the first disc, through which the pulp is forced. The disc refiner has the advantage over previous beaters in that it can be used continuously, rather than by batches of pulp.
Paper or card stock that is made with two sheets that have been laminated together. Each sheet may have a different texture, colour or finish appropriate to the usage.
On a papermaking machine the dry end is the end involved with the drying, calendering, reeling and slitting of the paper.
Elemental chlorine bleaching
Also known as chlorination (C) it is a bleaching process in which the pulp is exposed to gaseous chlorine, Cl2, which reacts with the lignin to make water and alkali soluble orange coloured chlorolignins. It was often the first stage of the five stage, CEDED, bleaching process that was used with Kraft pulp from the 1950s, until chlorination and chlorine derived bleaches were phased out after the 1980’s. It has been mainly phased out due to environmental concerns.
Elemental chlorine free
Is a pulp bleaching technique that may use chlorine dioxide, but not gaseous elemental chlorine.
A grass originating in North Africa or Spain that has been used in papermaking in Great Britain from the 1850s. It was first used in Great Britain by Thomas Routledge in 1857. It was often used in book paper. Esparto is rarely seen in American paper due to the cost of transport.
Printmaking paper used for producing etchings. Such papers are able to withstand dampening and soaking, are dimensionally stable in moisture, and are able to withstand the pressure of the printing press. Etching papers are either unsized or lightly sized, and many are rag papers or have a high rag content.
A wide range of fast growing hardwood trees that primarily grow in Australia, although they are now grown in plantations around the world. They were not able to be used in paper making machines until 1938, following research by Boas and Benjamin in Australia.
This is an impression on the paper that appears to be a watermark, however it was not created by the thinning of the pulp in the sheet as formed by a traditional watermark. These false watermarks have been created in a number of ways. One way was by drawing the design with an oily substance that make the paper translucent which makes the design appear lighter. Another way to make a false watermark is to impress the paper and emboss it at the dry end of the machine, as opposed to the wet end.
Long strand-like filaments that are usually derived from plant material used to form paper. Fibres are usually held tightly together in wood and need to be broken apart by mechanical or chemical means.
In wood pulp, fibrillation is the breaking apart of the fibres from each other into a dispersed pulp.
A chemical that is added to the pulp prior to the sheet forming that adds to the bulk, opacity, brightness and smoothness of the formed sheet. Kaolin and Calcium carbonate are common fillers.
The appearance or process which improves the surface or appearance of a sheet.
A traditional paper size based on inches, still in use in the USA. Foolscap measures 13½ x 8inches, or 13½ x 16inches for a full sheet. There is some variation in traditional sizing of up to half an inch. The name is derived from paper produced to this size in the UK bearing a watermark of a fool wearing a belled hat.
The first papermaking machine produced in England was granted a patent in 1801 and made in 1803, financed by the Fourdrinier brothers Robert and Sealy. This machine was based on the design by the Louis-Nicholas Robert of France who had taken out a patent in France in 1799 for a papermaking machine. The Fourdrinier machine formed the basic principles on which all later modern papermaking machines have been based. There is a wet end, which can encompass the headbox and the sheet forming section where the dandy roll passes over the still wet sheet, then the press section in which the paper passes through rollers to remove excess water, then the drying section in which the paper is further dried, and finally the calendering section where the paper is smoothed by rollers.
Red-brown spotting marks on paper that appear over time, and through the effects of moisture. Foxing is caused by a combination of metallic impurities and mould.
Fibres coming out from the surface of the formed sheet of paper.
A shrub growing in Japan whose bast fibres have been used in papermaking for centuries. Gampi has been used to make Torinoko paper for Kana script calligraphy.
A colourless mix of proteins and peptides derived from the partial hydrolysis of collagen from bones and tissues of animals. It was first used in papermaking in Fabrino, Italy in the mid thirteenth century and was commonly used in paper sizing before the introduction of alum-rosin sizing in 1807, although it was still widely used into the 1840s and 1850s.
A paper made from heavily beaten chemical pulp that has been supercalendered. This paper is smooth and dense on both sides it is also transparent or semitransparent. As it is resistant to the passage of oils, grease and smells it is often used in wrapping foods, tobacco, chemicals and greasy metal parts.
Paper produced on a machine and some handmade papers will have had the wet pulp shaken in one direction resulting in many of the fibres aligning in that direction. In machine made papers this is the direction of the continuous mesh on which the pulp is sprayed. Paper tends to tear more readily along the grain direction.
A mechanical pulp made by pressing debarked wood through a rotating grinder with water or steam. The pulp is generally short fibred and if not further chemically treated high in lignin. It is also known as Stone Groundwood Pulp (SGW), and if the grinding is done under pressure with heated water it is known as Pressure Groundwood (PGW).
The weight of a paper measured in grams per square metre. It is more accurately written as g/m2
A soft mineral composed of calcium sulphate dihydrate, with the chemical formula of CaSO4.2H2O. A form of it is alabaster which is used in sculpture.
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