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Everything you need to know about Paper

Everything you need to know about Paper

The perfect guide to help you select your papers!

This article offers a glossary of terms that you may see regularly in your GreatArt catalogue or online at www.greatart.co.uk, but do not necessarily understand how they define the product you are purchasing.

Paper
Acidity
Acids damage and weaken papers by provoking stains. That is why paper is made in a neutral environment using extremely pure water. This environment also protects the paper from outside acidity by adding a neutralizing alkaline stock (calcium carbonate). The addition of this is known as Buffering. The acidity of a paper is measured by the pH level. A pH 7 is called a pH neutral. The alkaline stock raises the pH to around 8.5.
Backing board
A board which is mostly made of wood-pulp. Used where it will not be visible, such as in framing.
Glued on 4 sides (or Block)
A Block of paper is a pad whose sheets are glued together on all 4 sides. This tightens them and prevents them from crinkling. Blocks are very useful for outdoor work, especially if you choose very wet technique, as they are more stable and normally have a very thick board at the base.
Bristol
A smooth and uncoated paperboard, as originally made in Bristol, England.
Cellulose
This is the fibres that make up the paper pulp, essentially coming from wood after the elimination of lignin.
Coated
Paper that has been ‘coated’ on its surface, allows for thinner and more precise lines. The surface can be glossy or matt. It offers the possibility of correcting mistakes by scratching.
Cold Pressed
A paper surface with a slight texture, formed by pressing the finished sheet between cold cylinders.
Paper
Cotton (linters)
This is the fibres which come from the linters which is the short part of the cotton flower that is left after the elimination of the long fibres for textile use. Its price limits its use to certain papers of superior quality. The cotton comes from the cotton plant that can reach up to 7 metres high in a wild state. Two months after it is planted, the branches are covered with flowers which, once withered, turn into cotton wool spots. The cotton wool spots contain seeds wrapped in white fibres. Those white fibres are mechanically removed from the cotton seed to obtain the “linters”, also called “flocks”. The linters are used for papermaking. Its fibres are 2 to 3 mm and very resistant. The cotton linters are transformed into sheets and stocked in bales.
Cylinder Mould
The cylinder mould is a very traditional paper making machine. The paper sheet is formed on a large cylinder partially immerged in a vat where the paper is maintained in a liquid state at a certain level. The fibres adhere to the emerging part of the cylinder and a felt applied onto the rotating drum carries the wet fibres as they combine to become a sheet of paper. This sheet then goes through the pressing section and eventually into the drying cylinders.
Shaped or Deckle Edges
When the paper is handcrafted, the diluted pulp is dropped onto the sieve or mesh and left to drain. The irregular edges formed by this process are then left on the sheet. Nowadays it is the same principle, but sometimes the sieve is fixed onto and irregular shaped frame, hence the “shaped edge” expression.
Paper
Filler
This is added to the paper to increase the waterproof qualities, the opacity and the dimensional stability. They reduce the mechanical resistance of the paper. Commonly used fillers are Kaolin, Talc or titanium oxide.
Fungicide
Treatment preventing the paper from becoming mildewed in damp conditions.
Gelatine
Natural gelatine protects the cotton fibres and prevents the pigments from sinking inside the paper.
Grain
Examples are softened, NOT (fine grain), Hot Press (smooth) and Torchon (rough). The grain is formed by the print left by the contact of the felts. Different techniques require different surfaces, but personal preference will also influence the choice of the artist.
Hot Pressed
A paper surface with a smooth texture, formed by pressing the finished sheet between hot cylinders.
Kaolin
Avery pure white clay variety used as a filler in the pulp or in the mix designed to cover coated papers.
Laid
Paper with watermarks constituted of thin, parallel and perpendicular lines forming a grid pattern. The marks come from the pulp resting on the mesh during fabrication.
Marking
It signs the paper, identifies it and guarantees its authenticity. The different processes are the toothed wheel marking, the dry stamping and the watermark.
Mass-coloured
In order to colour a paper colourants can either be introduced into the pulp or simply on the surface in a later phase of the fabrication. The difference is visible when the sheet is torn. Mass-coloured paper will have the same shade on the surface and inside.
Paper
Mould
Paper made with a frame the exact size of the intended sheet, the mould. After the spin-drying, the sheets are pressed between felts and air-dried.
Optical brightener
A fluorescent colourant that when added gives the paper a bright white shade and tones down the yellow colour of the natural cellulose fibre.

PH neutral
Expression used for an acid-free paper which will be perfectly preserved throughout time and whose colours will keep all their brightness.
Pulp
Fibre which is cleaned and beaten into a wet mixture used to form paper
Quire
A measure of paper quantity, normally 25 sheets.
Rag
Often referring to cotton rags which were previously used as the raw material to make paper. Rag content is the amount of cotton fibre relative to the total material used to make the paper.
Ream
500 sheets (20 quires).
Satin-like
Paper described as such have a smooth, grain-free, and non glossy surface (resembling satin).
Sizing
The addition of starch or gelatine size into either the pulp or onto the surface of the paper to limit the penetration of liquids (ink, watercolour, gouache) and pigments.
Tooth
A very slight surface texture which is normally preferred for drawing.
Vellum
The name comes from the Latin for calf, a skin which was used for the fabrication of the thinnest parchments. It is a smooth or grained, translucent paper typically used for drafting.
Watermark
The watermark is a translucent image reproduced inside the paper sheet that is visible when the sheet is held to the light. It is actually the result of a difference of thickness of the paper pulp inside the sheet and is normally the signature stamp of the papermaker or logo of the manufacturer.
Weight
The density of the paper or cardboard surface per unit area. It is normally expressed in grams per square metre (for example 80 gsm). The higher the rate, the more resistant the paper is to successive layers of colours.

Louise from GreatArt

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1 comment

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  • The information about the different types of art paper is really useful. Could it be
    shown in a darker form please because when the pages are printed off to keep
    as a permanent and very useful reference they are so pale as to be almost un-
    readable.