An essential basic when painting in watercolours, watercolour paper comes in many guises and has been produced for centuries since paper was first manufactured 2000 years ago. Higher end quality watercolour papers have traditionally been made from cotton rag, whilst today there are many wood pulp based watercolour papers available which are perfectly capable of producing superb results.
“Rag paper” is traditionally made from cotton or linen, and can be from old recycled clothes or from new material, it contains longer fibres than wood pulp papers and is naturally acid free. Papers made from wood pulp use the cellulose created when beating the pulp and are both wood free, lingnin free and ideally acid free, although some degree of alkalinity is acceptable as paper can naturally draw acid from the environment.
There are three main ways of paper manufacture, Handmade, Mouldmade and Machine made each has its own merits and also drawbacks. Handmade is as the name suggests both time consuming and therefore more costly but can produce exquisite watercolour paper, it is manufactured using a mesh frame which is dipped into a vat of pulp and then rocked from side to side in all directions during which the fibres are weaved into each other creating a very even and particularly strong layer of paper, this is then stacked between felts and left to dry. The felts used create the degree of texture on the surface of the paper producing the rough surface so popular with watercolourists.
Mouldmade paper is produced on a cylinder mould machine whereby the pulp flows along felt conveyor belts and is pressed into the felt to create the tooth or texture of the surface of the paper and subsequently dried whilst passing around heated cylinders. As the paper flows along belts the fibres form a directional grain along the length of the paper and the paper has deckle edges either side, it is often formed into a roll which will be subsequently cut into flat sheets. A much more economical process for producing paper than Handmade yet able to produce quality watercolour paper, both wood pulp based and rag papers, or often a combination of the two.
Machine made paper is by far the most prolific method of paper production today and the most economic form of manufacture and will also produce the most consistent specification. It does however have drawbacks when producing watercolour paper, in particular a grain direction is inevitably created as the fibres forming the paper are travelling at high speed along a conveyor belt, no deckle edge will be evident. Machine made paper has to be dried relatively quickly due to the volume manufactured by passing the paper through heated rollers on the paper machine as it is made, whereas true handmade paper is usually left to dry naturally, sometimes taking several days to dry thereby helping to create the toothy textured surface so revered by watercolour artists.
Watercolour paper, alongside most other papers requires sizing In order to prevent the paint simply being absorbed into the paper. Sizing is in effect a coating on the fibres that make up the paper, whether from wood pulp or indeed rag, it can be applied in a number of ways, by either spraying the paper once dry, dipping the paper in a vat of size or more popularly these days by adding to the pulp known as internal sizing. Gelatin size made from animal skins is the most popular form of protection and has been used for centuries, but there are now vegan sized papers with plant based synthetic sizing appearing on the market.
Modern watercolour paper is usually manufactured by pressing the pulp into woollen felts during manufacture to create the tooth or texture and is traditionally available with a choice of three surfaces. Rough, which as the name suggests has a rough texture achieved by pressing the paper into the woollen felts and would be considered the most traditional surface and is particularly effective when painting landscapes or seascapes. Hot pressed often known as HP, is a very smooth surface paper achieved by subsequently passing the paper sheet through heated rollers during the drying process, although this paper will have a slight tooth it is a smooth paper nonetheless and very popular for architectural drawings or botanical painting where detail is paramount. Finally Cold pressed often called NOT surface (i.e. not hot pressed) in which a lesser pressure has been applied when pressing the pulp into the felts producing a surface that is neither smooth nor rough but is probably the most popular surface for beginners.
There are many and varied watercolour papers on the market today and even papers with colour tints which provide an alternative base from which to work. Some watercolour papers are pure cellulose base (from wood pulp), some 100% cotton and some a mixture, there is not one type or brand that is right or wrong, better or worse and it is often pure personal preference and will vary according to each individual artists style or painting technique. Heavier weight papers are undoubtedly more expensive however they are often more forgiving if you need to correct work and the few pounds saved buying the cheapest paper can pale into insignificance when compared with the time spent overall on a finished painting.
Some of the most popular watercolour papers in the UK are Waterford which is rag based and Bockingford, which is wood pulp based and therefore more economical, both are manufactured in St Cuthbert’s mill in Somerset and made by traditional methods using a paper making machine dating back to 1907 albeit upgraded for use today. A short video is available showing watercolour paper manufacture in the present day.
