ABSORBENCY:
The extent to which a paper will soak up and hold liquid. This can be altered by adding size.
ACID - FREE:
Paper that, if infused in water, yields a pH of 7 (neutral) or slightly above (alkaline). Paper made without rosin and alum sizing. It can be made from any cellulose fibre if the active acid pulp is eliminated during processing. It is also lignin and sulphur-free. Ensures the longevity of important documents and artworks, safeguarding them against discolouration and deterioration over time.
ARCHIVAL:
Especially permanent, durable acid-free paper. Archival paper is meant to be used for publications of high legal, historical, or significant value. Cotton paper is often used for archival purposes, as it is not made from wood-based pulp.
Archival or Museum grade: cotton rag paper made from cotton pulp / Conservation grade: acid-free, buffered paper made from wood-based pulp.
BINDER :
Adhesive employed to stick a layer of coating together and to the surface of a paper or board. Starch is the most frequently used – synthetic binders (latex) are also sometimes used for improved performance.
BUFFERED / UNBUFFERED :
Calcium carbonate (chalk) can be added to paper pulp during the paper making process as a buffering agent – or ‘buffer’. This raises the pH level of the paper to the alkaline side of the scale.
Buffered tissues and storage boxes / mountboards are recommended for use with most paper and cellulose based items because of their ability to neutralise acids and extend the life of paper, photographs, textiles, and artefacts.
Unbuffered papers are thought to be preferable for use with materials that come from animals, this is due to the proteins which provide the item’s structure. These items include silk, wool, leather, feathers, animal specimens, horsehair, pearls and so on. Blueprints, Cyanotypes and Albumen photographic prints are best stored using unbuffered materials.
CALCIUM CARBONATE :
Added to paper to make it alkaline. Cellulose in low grade acidic papers crumbles and degrades over time. Alkaline papers will absorb acidity found in atmospheric pollution protecting the sheet from decay.
CALENDERED :
A calender is usually found at the dry end of a papermaking machine. It is comprised of sets of rollers that smooth and polish the paper.
CARTRIDGE PAPER :
A strong paper with a slightly textured surface used for a variety of purposes. Originally developed for use in the tube section of shotgun cartridges from which it derives its name.
CHEMICAL PULP :
Pulp made from wood chips treated with chemicals to dissolve the lignin and separate out the cellulose fibres. It can be bleached or unbleached.
COATED PAPER :
A layer of minerals can be applied to paper on one or both sides to improve printability and brightness. Most often this is china clay (hydrated aluminium silicate). Calcium carbonate and titanium dioxide are also used; the coating is held together and attached to the paper using a binding agent.
COCKLING :
The uneven rippling caused by the expansion of paper when water is applied.
COLD PRESS :
A term used to describe the surface of watercolour paper. A slightly textured surface that lends itself to a variety of work. Also known as ‘NOT’ as in ‘not hot pressed’. To make cold pressed paper, sheets of cellulose pulp are pressed through felt covered metal rollers at a cold temperature – hence “cold press”. The felt rollers and the drying process result in the texture.
COTTON RAG :
Cotton rag is the purest form of cellulose available and allows papermakers to make the finest archival papers.
DECKLE EDGES :
The natural rough edges found on handmade and mould made papers. Formed by the ‘Deckle’ a frame attached to a paper makers mould to delineate the outer edges of the sheet.
EMBOSSED MARK :
A logo pressed into a sheet of paper to prove authenticity of its maker and origin.
FILLER :
Used to increase opacity and create a smoother texture to a paper. Often China clay or calcium carbonate.
FOURDRINIER MACHINE :
A mechanical papermaking machine that forms paper on a continuous wire belt. Named after the Fourdrinier brothers who financed the first operational machine at Frogmore Mill in Hertfordshire, England. It is still in use to this day – we offer a selection of Fourdrinier papers from Frogmore Mill within our range and our popular ‘Shepherds Machine Age Compatible’ paper is made on this machine.
GAMPI PAPER :
Paper made from gampi fibres – traditionally made in Japan where this plant is indigenous. Gampi was the earliest plant used and is considered the noble fibre, noted for its richness, dignity and longevity. It has an exquisite natural sheen and is often made into very thin tissues. Gampi has a natural 'sized' finish which does not bleed when written or painted on. Gampi resists cultivation and is mainly harvested in the wild. It is increasingly difficult for papermakers to acquire Japanese-grown gampi.
GRAIN DIRECTION :
The direction of the majority of the fibres in a machine-made paper. The direction is parallel to the movement of the pulp on a Fourdrinier paper machine. Over 50% of the paper fibres will position themselves in this direction. Machine made papers can expand as much as three times in the cross direction as opposed to grain direction when humidity varies. This can result in rippling or stretching in the cross direction when paper is wet.
Paper is more pliable and less resistant with the grain – it will fold more easily and rip more readily. When going against the grain, depending on the weight of the paper - folding or tightly rolling may result in buckling or cracking of the fibres.
The fibres in hand made paper are evenly distributed and do not have an obvious grain direction and the issues that this causes. They are therefore stronger and easier to use.
See also reference to the importance of grain direction in our BOOKBINDING glossary.
GRAMMAGE or GSM :
The term used to denote the weight of a paper. This measurement is the weight of a single sheet one square metre in size. It is expressed as grammes per square metre (g/m2) or gsm e.g. 100gsm.
Book papers range typically from 80 – 160gsm.
Card weight papers or watercolour / printmaking papers 180 – 350gsm.
Heavy weight papers / boards in excess of this.
HANDMADE PAPER :
Paper sheets made by hand individually in the traditional manner. Pulp is made by beating / macerating the raw materials to soften the fibres whilst suspended in water. This resulting pulp is then poured into a trough containing a large amount of water - approx. 90% water to 10% fibres. Size, colourings and bufferings are added at various stages.
The paper mould is made of fine wire mesh and a wooden frame. To produce a sheet of paper a wet layer of pulp is formed on the mould. The papermaker scoops exactly the right amount of pulp required for each sheet. Usually, a stack or ‘post’ is made of numerous sheets – this is then pressed with blankets / felts several times in various relayering processes to expel excess water.
The damp sheets are pasted, hung, or laid out to dry in a special drying place or dried by heat. Size may then be applied to the surface of the sheet before sorting, finishing and packing. There are many differences in the papermaking practices of various countries.
HOT PRESS :
A term used to describe the surface of paper. Hot press is the smoothest finish and allows for highly detailed work. This surface is favoured by botanical artists and any situation where a smooth finish is required. The paper is finished on hot rollers.
KOZO PAPER :
Kozo (paper mulberry) is the most widely used fibre for papermaking in Japan. It has the longest fibre and makes the strongest paper. It is grown as a farm crop, and the branches are cut annually. The plants will regenerate continually for about 40 years. Commonly used for printmaking – some are suitable for wet media.
KRAFT PAPER :
Paper made from a type of chemical wood pulp; it may be bleached or unbleached and produces a strong paper often used for wrapping and packaging. The term derives from the German word for ‘strong’.
LAID PAPER :
A paper with watermarked lines – more prominent on one side than the other and clearly visible when held up to the light. The small regular lines are left behind on the paper when it is handmade in a mould made from rows of metal wires or bamboo. Laid lines are very close together. They run perpendicular to the "chain lines", which are further apart. Often used for stationery, endpapers for books and for pastel and chalk work where a texture is favoured.
LIGNIN :
A naturally occurring chemical compound that is found in wood that binds the fibres together. Paper made with pulp containing Lignin, with time, goes yellow and isn’t archival (for example, newspaper and paperback books). Archival grade pulps have the Lignin chemically removed and are known as Woodfree.
LOKTA :
Lokta paper, also known as Nepali kagaj or Nepali paper, is a wildcrafted, handmade artisan paper indigenous to Nepal. It is made from the bark of two of the species of the shrub Daphne. This paper is used to make notebooks, religious scriptures and the arts. Lokta paper's durability and resistance to tearing, humidity, insects and mildew have traditionally made it the preferred choice for the recording of official government records and sacred religious texts.
MACHINE-MADE PAPER :
A paper machine (or paper-making machine) is an industrial machine which is used in the pulp and paper industry to create paper in large quantities at high speed. Modern paper-making machines are based on the principles of the Fourdrinier Machine, which uses a moving woven mesh to create a continuous paper web by filtering out the fibres held in a paper stock and producing a continuously moving wet mat of fibre. This is dried in the machine to produce a strong paper web.
The basic process is an industrialised version of the historical process of hand papermaking, which could not satisfy the demands of developing modern society for large quantities of a printing and writing substrate. The first modern paper machine was invented by Louis-Nicolas Robert in France in 1799, and an improved version patented in Britain by Henry and Sealy Fourdrinier in 1806.
Machine-made papers have a clearly defined grain direction.
MECHANICAL PULP :
Pulp made by mechanically grinding wood. This type of pulp includes Lignin and other impurities. It is not archival and is used for low-grade papers like newspaper.
MITSUMATA :
A fibre indigenous to Japan and grown as a crop. Known as the "feminine element": graceful, delicate, soft and modest. It results in a beautiful and delicate paper. Mitsumata takes longer to grow than other fibres typically used for making washi papers and is thus more expensive.
MOULD-MADE PAPER :
Mould-made paper refers to paper made on a Cylinder Mould Machine. The paper is made on a revolving wire covered cylinder. This process produces a mechanised ‘handmade’ style paper. The fibres lay more randomly throughout the sheet making it much stronger than a machine-made paper.
OPACITY :
The property that limits the light visible through a sheet of paper. In a paper with good opacity the printing or writing will not normally be visible on the other side.
PAPER :
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses, or other vegetable sources in water. The water is drained through a fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines - some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year.
The oldest known archaeological fragments of the immediate precursor to modern paper date to the 2nd century BC in China. The pulp papermaking process is ascribed to Cai Lun, a 2nd Century AD Han court eunuch.
It has been said that knowledge of papermaking was passed to the Islamic world after the Battle of Talas in 751 AD when two Chinese papermakers were captured as prisoners. Although the veracity of this story is uncertain, paper started to be made in Samarkand soon after. In the 13th century, the knowledge and uses of paper spread from the Middle East to medieval Europe, where the first water-powered paper mills were built. Because paper was introduced to the West through the city of Baghdad, it was first called bagdatikos. In the 19th century, industrialization greatly reduced the cost of manufacturing paper. In 1844, the Canadian inventor Charles Fenerty and the German inventor Friedrich Gottlob Keller independently developed processes for pulping wood fibres.
RATTLE :
The distinctive sound a particular paper makes when shaken loosely.
REAM :
A unit of measurement of sheets of paper – usually 500.
ROUGH :
A heavily textured paper – often used to describe watercolour paper. The surface is created with the texture of the felts and minimal pressing in comparison to Hot or Cold press papers.
SHOJI :
A shoji is a door, window or room divider used in traditional Japanese architecture, consisting of translucent (or transparent) sheets on a lattice frame. Shoji paper is a generic term for the type of paper suitable for this purpose. Often available on rolls to allow for screen making.
SIZING :
Size affects the absorption of liquid into paper.
Internal Sizing – A chemical is added to paper to give it water resistance. This stops watercolour paint or ink from being absorbed into the sheet.
Surface Sizing – The application of a product (such as gelatine) to paper by submersing it in a bath (or tub) of liquid. It enhances the holdout of the sheet or increases the surface strength. Gelatine surface sized paper is not vegan or vegetarian (also called ‘gelatine sizing’, ‘tub sizing’ or ‘external sizing’).
TOOTH :
The texture of a paper is described as ‘tooth’.
WASHI :
Washi is the Japanese word for traditional papers made from a variety of renewable plant fibres. Wa means Japan, and shi means paper.
Japan has a long history of producing washi for everything from utilitarian tissues for cleaning swords to kamiko for making clothing to surfaces for the creation of the finest calligraphy, paintings and prints.
Washi was once used in virtually every facet of life in Japan. While there are far fewer papers being made today, and washi is no longer ubiquitous in Japan, there remains an astonishing array of papers in production.
WATERCOLOUR PAPER :
Frequently with high cotton content this paper is sized internally and externally to maximize suitability for painting with watercolours. Available in three surface finishes: cold press, hot press and rough and several weights.
WATERLEAF :
A very absorbent paper with no sizing. Eg. blotting paper.
WATERMARK :
An impression formed by a design in wire sewn or soldered on to a handmade paper mould or dandy roll at the end of the machine-made process. The watermark is visible when you hold the paper to the light. On handmade and mould-made papers the watermark is very clear. Watermarks are famously used as a security measure on banknotes.
WOOD-FREE :
Paper made entirely from chemical pulp and free from wood-based impurities such as lignin, which are present in mechanical pulp. It is archival.
WOVE PAPER :
Paper first made around 1754 formed on a mould with a cover of woven wire cloth, hence ‘wove’. Paper with an even opacity in common use today.