No matter the method of paper-making, at the beginning of the process is the production of paper stock. The main constituent of the stock is pulp, a fibrous material made by beating or refining rags, wood, or other plant matter in order to extract the cellulose fibre, the key component of paper.
Above image: Kieren at Two River’s Paper Company
By the second century AD, Chinese papermakers had developed a papermaking method which resembles that still used today, characterised by the dilute suspension of cellulose fibers in water. They made pulp using the bast fibers of the kozo plant, bamboo, hemp rags, straw, or scraps of fishing nets, beaten to make a fibrous slurry.
When papermaking reached Europe in the thirteenth Century, pulp was made primarily with hemp, linen, or cotton rags. These materials continued to be the main source of cellulose fiber in papermaking until the nineteenth century, when the increasing demand for paper and the invention of industrial papermaking machines led to the use of wood as a source of cellulose fibre. The earliest industrial wood-based papers were made by mechanically grinding the wood into a pulp. This meant that the paper contained a high amount of lignin, a polymer found naturally in wood which causes paper to become yellow and brittle in a relatively short period of time.
As a result, chemical pulping processes were developed to remove lignin and other impurities in order to make longer lasting paper. This is what is known as ‘wood-free’ paper, in which the ‘woody’ components that compromise longevity have been removed during manufacture, leaving only the cellulose fibres. Artist-quality papers are made using chemical pulp, while mechanical pulp containing lignin is still used to make newsprint.
Rag papers, handmade printmaking papers.
The process of making paper by hand has barely changed for hundreds of years. Handmade papers are made sheet by sheet, not in a continuous roll. The sheet is formed by pouring the stock onto a mould, which is a hand-held wooden frame with a stainless steel wire mesh draining surface. The sheets are interleaved between woollen felts and pressed to remove excess water. The paper is then tub sized with gelatine or another sizing agent, and air dried.
Artist handmade watercolor paper is usually made with 100% cotton and/or linen rag, which is recycled cloth. Because of the longer fiber length, which in comparison to the cotton linters used in cotton artist papers forms a more robust weave within the pulp that makes each sheet, meaning that handmade is more durable and more able to withstand heavy treatment.
Printmakers utilise many Asian handmade papers which can be lighter and smoother than cotton rag papers. Fibers from the inner bark of shrubby plants have a high cellulose content and long fibers. Processing involves teasing and beating the fibers apart as opposed to cutting them. The thinnest Japanese papers make use of neri, an addition to the pulp that slows down the rate at which the water drains through the mould. This delay creates time to tilt the mold in various directions, really intertwining the long fibers to increase the strength of the paper.
The smooth surface on the front of these papers is created by brushing them out to dry onto metal sheets. The sizing and texture may vary between batches of handmade paper, and the sheets usually have four genuine deckle edges.
Cylinder Mold-Made Paper
Most artist-quality cotton watercolor and printmaking papers.
Cylinder mold machines consist of a vat and a cylinder mould. The paper stock is picked up from the vat by a slowly rotating cylinder mould. The cylinder is covered with a wire mesh and, as it rotates, the water flows through the mesh and the pulp forms a web on the outside of the cylinder. The fibrous sheet is transferred onto a continuously moving-lined belt and processed further through the different sections of the machine, depending on the requirements of the paper. The paper is pressed, either between rollers lined with felt to create a rough texture, or hot metal rollers to achieve a very smooth surface.
As with handmade paper, the paper fibers are orientated in random directions, giving cylinder mold-made papers excellent surface stability which is an asset to all painting and printmaking processes.
Cylinder mold-made paper can be seen as the ‘halfway’ point between handmade and Fourdrinier machine-made paper. The process makes more consistent paper than handmade paper, but is more sensitive to the characteristics of the material than industrial machines.
Full sheets of cylinder mold-made paper have two genuine deckle edges, and may also have two edges which have been cut to resemble genuine deckle edges.
Fourdrinier Machine-Made Paper
Cartridge paper, tracing paper, newsprint.
The Fourdrinier machine, named after Sealy and Henry Fourdrinier, was patented in 1806 in response to the growing demand for paper. Instead of making each sheet by hand, the paper pulp could be dried, pressed, and textured by a series of mechanised rollers, allowing manufacturers to make consistent batches of paper very quickly. Although there were developments following the first Fourdrinier machine, the process today still remains very similar.
The paper stock is spread over a mesh conveyor belt which removes the water from the fibers with a vacuum. It is then pressed through large heated rollers to squeeze out even more moisture. Further series of rollers are also used to smooth the paper surface, or add texture if necessary, and to ensure uniform thickness throughout the sheet.
The paper emerges from the machine in giant reels.
Fourdrinier machines are known for their efficiency, producing high volumes of low cost, utilitarian papers, usually used for stationery and printed matter.
However some of the oldest and most renowned mills use their Fourdrinier machines to make artist papers. Using high grade cellulose, they benefit from being strong and archival as well as economical.
How to Tell Front From Back?
When the paper pulp is captured on the cylinder mould, or on the machine belt, the water will drain through some form of mesh. Contact with this mesh will form a pattern on what is considered the back of the paper. The paper is then placed or pressed onto natural woollen felts, metal sheets, or in the case of machine-made paper, pressed with marking felts to give a particular texture, or run through calendar rollers to polish the surface smooth.
For many machine-made papers, like cartridge paper, there is no discernible difference between the two sides. For cylinder mold-made papers you will find a regular texture on the back (the mold side) and a more random texture from the natural felts used on the front (the felt side). The exception to this would be papers stated as offering a completely smooth drawing or painting surface, which may have more texture on the underside. If the paper has a watermark, when you hold it up to the light, the side on which the watermark is the right way round is the felt side. However, it is down to personal preference and there is no reason why you can’t use either side.
Watch our On Location film to see paper being made at the Two Rivers mill:
Watch our On Location film to see paper being made at the St Cuthberts paper mill:
View paper at Jacksonsart.com