Everything You Ever Wanted to Know About Watercolour Paper

We originally published this as a 5-part series ‘All About Watercolour Paper’
– now posted here in one long article.

All About Watercolour Paper

Good watercolour paper is versatile, strong and enhances the appearance of your watercolour painting.

Hand-made, Mould made and Machine Made.

There are 3 main varieties of watercolour paper –
Here’s a description of the differences.
Handmade paper – Tends to be made of 100% cotton and is very durable. The irregularity of the surface of handmade paper is very desirable among some watercolour artists. It tends to be heavier than other watercolour papers and so does not require stretching. Because of its high durability it can withstand scrubbing and lifting of colour from its surface without showing visible damage.

Mould Made paper – Mould made paper is made by a machine which consists of a stainless steel vat and a cylinder mould, which is usually up to around 260cm in circumference and 130cm in width. The cylinder is placed in the vat, and a very dilute mixture of pulp and water is pumped into the vat. This mixture forms a fibrous web on the cylinder mould. This fibrous web is then pressed to varying degrees to form the varying surfaces available. Some cylinders have deckle frames on them which enable them to replicate the deckled edges of handmade papers. Mould made paper manufacture can also produce rolls of watercolour paper. Many artists favour mould made watercolour papers as they are more consistent in their durability than handmade papers but match their beautiful surface textures.

Machine made (fourdrinier) papers – Are made using a flat machine that consists of a forming section (where a slurry of fibres is filtered out on a continuous loop to form thin ‘sheets’ of the wet mixture), the press section (there is sheets are then pressed to remove as much of the water content as possible), the drying section (where the sheets are then snaked through a number of heated cylinders in order to remove more of the moisture so that the sheets contain around 6% of moisture) and the calendar section (where the paper is smoothed into flat sheets). This process of making paper is least sensitive to the characteristics of the materials used, and tends to be less favoured by artists. However, they do produce paper consistently.

Paper Weight and Surface Textures

The Weight of Paper
Paper weight is either measured in grammes per square metre or by lbs per ream. Jackson’s Art Supplies sells paper of a variety of weights, from 90lb – 560lb. We recommend stretching paper that is lighter than 250lb in weight as it is more likely to warp when watercolour is applied to its surface if not stretched. The very heaviest weights tend to be handmade papers that have texture.

Watercolour Paper Textures
Watercolour paper is available in 3 textures, although there are some pads and blocks that are not available in all 3 textures, so it is worth having a look through what is available in each range.

What is Hot Pressed paper?
Hot Pressed paper tends to be favoured by artists that like to work delicately and with a lot of subtle detail, for example botanical artists. It is the least textured surface, and is completely smooth as it is pressed between 2 hot metal rollers. It is also favoured by artists who will want to reproduce their watercolour on smooth paper.

What Does ‘Not’ mean?
Not and Cold Pressed paper amount to the same textured surface – this is the name given to paper with has a slight tooth to it. It is the most popular surface for watercolour painters as it allows for a little texture in your work, as the paint will sink a little into the dimples on the surface of the paper, but it will also be sympathetic to some detailed work. It is made by pressing through the cold metal rollers. It is thought to be the easiest watercolour paper surface to work on.

Rough surface paper
As one might expect, rough surface paper is the roughest texture paper available. It is pressed between sheets of textured felt during the drying process, which is why it has a felt like texture. The heavier ingrain of texture means that granulating (irregular colour application) effects are enhanced. This paper surface is not recommended for those interested in detailed work and is more suited to bolder, more expressive painting techniques.

Paper Sizing and Stretching

Watercolour paper sizing
Watercolour paper is traditionally sized with gelatin so that the watercolour paint does not sink straight into the paper. The gelatin provides a little resistance and forces the paint to sit on the surface and only partially sink into the paper. Paper can be sized with gelatin internally or externally. Internal sizing is when the gelatin is added to the water and pulp mixture before the paper has been made, and external sizing is when the sheets of paper once made are soaked in a gelatin bath. Internal sizing ensures that the paper does not become more absorbent even after scratching or scrubbing the surface of it. Many high quality papers are both externally and internally sized. If the sizing on a paper has been too heavily applied then it can easily be removed by soaking the paper in a bath, then removing and sponging the excess water off before leaving it to dry. This process is usually done anyway if the paper is being stretched by the artist. You will know if a paper has excessive sizing if the paper is resisting the paint more than it should, i.e., it forms as ‘bubbles’ of colour that gather on the surface of the paper.

How to stretch watercolour paper using Gummed Brown Paper Tape
The most common and inexpensive method of stretching paper is to begin by soaking it in clean water. For large sheets of paper it may be best to fill your clean bath with 5-6” of lukewarm water. Slide the paper carefully into the tub and leave it to soak for a few minutes. This will dissolve a little of the sizing of the paper. Carefully lift the wet paper from the tube and lay it on to a clean and dry board – a plywood drawing board would work fine. Sponge off the excess water gently, with a clean sponge – the outward motion you use to do this will help flatten the paper on to the board. Once you feel that the paper is adequately stretched out, wet your gumstrip and fix this to the outer edges of the paper, so that half is stuck to the board and half is stuck to the paper itself. I find that by putting the tape into the same bath water and then sponging off the excess water in the same way that you did with the watercolour paper works very well. Lay flat and allow this to dry (in the sunshine it doesn’t take too long, but it may need to be left for a morning, afternoon, or overnight to be completely dry) before you start your painting. When your painting is finished leave it to dry completely before cutting the paper free form the board using a sharp craft knife.

How to use a Paper Stretcher
Paper stretchers make the use of the gum strip tape redundant. You just need to soak the paper in the same way you would with gumstrip paper stretching but then fix the paper to the frame. Our economy paper stretchers and the Keba Artmate paper stretchers work in different ways. The economy paper stretchers consists of 4 bars and clip together – make sure that your sheet of paper is the right size for the frame you are using, immerse in water and then clip the frame around it, which will keep the paper taut. It is a lightweight paper stretcher and works better in the smaller sizes. The Keba Artmate paper stretcher has a backing board supplied and you can achieve a tighter stretch with it – if it becomes slack there is a key to tighten the frame again if necessary. There are 2 ways of stretching watercolour paper with the Keba Artmate – either you spray the back and edges of the paper to stretch, by doing this you can start to paint straight away, or you can soak the paper and stretch, allowing it to dry fully before work. The Keba can also be used for temporarily stretching pieces of silk or canvas for painting.

Paper Making Materials

What is the difference between Cotton Paper, Woodfree paper and Bamboo paper?
In our glued pads we do 3 varieties of paper – cotton, woodfree and bamboo, and we are often asked what the differences are. 100% cotton paper is generally considered the best quality. It is made from cotton linters which may have been taken from cotton rags. In the case of Khadi papers the linters are literally taken from old t-shirts! The length of these fibres is a lot longer than wood fibre and this makes cotton paper a lot stronger and more durable. It is also acid free which means that it will not deteriorate over time (acid can cause papers to yellow and become brittle).

Bamboo paper has been used in Chinese arts for hundreds of years, and Hahnemühle have reintroduced it as a low cost alternative to cotton papers. Bamboo is a highly sustainable material and so its use in paper making is considered incredibly environmentally friendly. Bamboo fibres again are relatively long which contributes to the strength and durability of the paper. It is naturally warm white and so it does not require any bleaching processes, which is also environmentally friendly and contributes to the longevity of the paper. The Hahnemuhle Bamboo paper is made of 90% bamboo fibre and 10% cotton, with a lovely unique surface.

Did you know that ‘Woodfree’ paper usually contains wood?
Woodfree is a shortening of the term ‘groundwood-free’ and what this actually means is that the woodpulp used in the paper manufacture has been broken down chemically as opposed to mechanically. This removes the lignin in the woodpulp, which is the substance that holds wood fibres together, and by removing the lignin the paper is strengthened, whitened and made purer. The acid content is removed which minimises discolouration over time.
Artists should avoid using any papers that have wood content that has been ground mechanically is it will not be stable and long lasting.

Extra White Papers

A note about extra white/high white papers
Extra white and high white papers at present can not be described as having a bright white appearance. They are whiter than their traditional countrparts, but are still creamy white. This is currently as white as can be achieved without compromising the stability of the paper. The extra whiteness is achieved by adding a little bleach to the paper, as well as a small quantity of titanium dioxide pigment. Optical brightening agents (which can be found in lesser quality papers such as Fabriano 5) are not used as their effectiveness deteriorates with exposure to light and as a result, the paper will appear to become yellow after significant exposure to UV rays.

Watercolour paper is available in the following formats at Jackson’s Art Supplies:

Watercolour Glued Pads
Glued pads are glued on one side only. Jackson’s Art Supplies sells a number of brands of varying qualities. The highest quality brands of glued pads are by Arches Aquarelle, Saunders Waterford and Langton Prestige. These pads are all 100% cotton which means they are the papers least likely to yellow, and the most durable as well. More detailed descriptions are given in order of quality in the watercolour glued pads section.

Watercolour Paper – Loose Sheets and Rolls
Traditionally, watercolour paper sheets come in the imperial size which is 30” x 22”, and there are usually 2 or 4 deckled edges depending on the method of manufacture. The larger your sheet of paper the more susceptible it is to cockling if it is worked on with fluid applications of watercolour paint, and so generally stretching is recommended for full imperial sheets of paper. If your paper has been cut into half imperial or quarter imperial size then generally it may not be so necessary to stretch the paper if the weight of it is greater than 200lb. At Jackson’s Art Supplies we sell a wide range of different watercolour papers, the majority of which are either mould made on a cylinder or handmade. A full guide to the Watercolour papers we do in sheets and rolls can be viewed the in the ‘Watercolour paper – loose sheets and rolls’ section.

Watercolour Boards that do not need stretching!
Daler Rowney Saunders Waterford Watercolour Board, Arches Aquarelle Canson Board, Daler Rowney Line and Wash Board, and Crescent board.
Watercolour Boards are sheets of watercolour paper that have been mounted on to a rigid, acid-free and archival card. This means that they are rigid and do not require stretching. More information on our watercolour boards can be found in our ‘Watercolour Boards’ section.

Watercolour Blocks
A watercolour block is a pad of watercolour paper that has been bound on all 4 sides. Usually the block of paper is secured to a rigid sheet of card. The sheets of paper are bound while they are wet, which means that they dry flat, and when they are used, the binding keeps the paper flat regardless of how much fluid watercolour is applied to the surface. Watercolour blocks are very practical because there is no need to stretch your paper before work. As with all watercolour surface products, blocks are available in a range of brands and standard which are reflected in the price and suitability for varying levels. Below is a rough guide to what is available at Jackson’s Art Supplies, more information on all blocks is in the ‘Watercolour Blocks’ section.

Watercolour Blocks for Beginners and Students:
Hahnemühle Britannia
Hahnemühle Veneto
Hahnemühle Cornwall
Hahnemuhle Anniversary Block
Winsor and Newton Cotman
Jackson’s Watercolour
Clairefontaine Aquarelle Etival
Daler Rowney Langton

Watercolour Blocks for Professional Artist use:
Superior watercolour blocks are made of cylinder mould made or handmade cotton papers, that are more age resistant, even less likely to yellow, acid and chlorine free, resilient and more characterful in their surface texture. The watercolour blocks that are for sale at Jackson’s Art Supplies that fit this description are:
Arches Aquarelle
Fabriano Artistico – Traditional and Extra White
Hahnemuhle 300gsm
Jackson’s Eco Paper
Saunders Waterford Traditional
Clairefontaine Fontaine
The Langton Prestige by Daler Rowney
Hahnemühle Cezanne
Hahnemühle Leonardo
Hahnemühle Tiepolo

Postcard Pads
Postcard pads are a wonderful unique way of telling the tale of your travels to your loved ones. These postcards will withstand light applications of watercolour without buckling, and once you are done you can write your message, address and fix and stamp and your postcard is ready to send! The Hahnemuhle Watercolour Postcards are 230gsm, rough surface and measure 10.5 x 14.8cm. There are 30 postcards in a pack, and they come in an attractive metal tin. The Jackson’s Watercolour postcard pad is bound with a black gauze tape down one side. They are 350gsm and there are 12 postcards in each pad. Daler-Rowney puts 12 sheets of Langton watercolour paper in a postcard pad, 300gsm.

Click on the underlined links above to go to the materials on the Jackson’s Art Supplies website.