Painting & drawing blog

CHOOSING PAPER FOR WATERCOLOUR PAINTING

Hot or Not? And other questions…

Arches watercolour paper

Although watercolour isn’t necessary the easiest paint to handle, I always think of it as a simpler medium to use than oils because it doesn’t involve mixing the paint with any spirits or additional oil, and as far as choosing your watercolour paints go I think this is broadly true: you choose whether you prefer pans or tubes, pick your manufacturer and range, and off you go.

However there is one thing that beginners tend to find very confusing about watercolour painting and that’s the paper you’ll need to work on, because watercolour paper varies in a number of ways and these are defined (especially here in the UK) by an initially baffling lexicon of traditional terms that you may not be familiar with. Here I’m going to try to de-mystify all the different options and help you choose the type of paper that will best suit your level of experience and the type of painting you want to do.

THE PAPER SURFACE: ‘HOT’ ‘NOT’ OR ROUGH’

This is the first decision you’ll have to make and these terms relate to the degree of texture applied to the paper surface. All watercolour paper is sold as either Hot-press, Cold-press or Rough-press and in the UK these types are known just as ‘Hot’, ‘Not’ and ‘Rough’.

‘Hot’ (hot-pressed) paper

Hot-pressed watercolour paper is usually just labelled as ‘Hot’ in the UK. This paper is so-called because once created the sheets of paper pulp are pressed at high pressure between heated rollers covered in a smooth felt, creating a paper surface with a high density of fibres and very little ‘tooth’, or texture.’ Hot’ is the smoothest watercolour paper you can buy and the least absorbent, because those fibres are so tightly packed together. This also make is slightly more reflective than the other types and so your colours may appear slightly more vivid.

Hot watercolour paper
Hot-pressed watercolour paper (fine tooth). Photo credit: jacksonsart.com

Because your paint will sit longer on the paper surface before it soaks in to Hot paper compared to the other types it’s a little easier to rectify mistakes by immediately lifting off a colour you’ve applied before it dries using a paper towel or a brush. With Hot paper your paint colours won’t blend together as easily on the paper as they would do with a cold-pressed paper, and layers of washes will be more visible. For some people this is a positive feature – it all depends on your style.

Who would benefit from choosing Hot paper? Because of its fine grain, Hot paper is better for finer details. I choose Hot paper because I paint small, detailed portraits in watercolour and with a coarser grained paper it would be much more difficult to control my paint accurately with tiny brushes. Hot paper is usually the paper of choice of botanical illustrators who also paint in a detailed and precise way. Many other types of illustrators favour it for the same reason (although equally many prefer the ‘arty’ look of a textured cold-pressed paper) If you wanted to combine watercolour with pen and ink or any other media then Hot paper would be the best option.

‘Not’ (cold-pressed) paper

When I first bought watercolour paints I wondered what on earth ‘Not’ paper could be! In fact the ‘Not’ simply means ‘Not Hot’; or in other words, it just means that the paper was cold-pressed rather than hot-pressed. (This strange term in only used the the UK, in the US ‘Not’ paper is called ‘Cold-pressed’) There is an additional difference which is that those cold rollers that the paper pulp is pressed through are covered in a much more textured felt which imprints a coarser surface to the finished paper.

Cold pressed watercolour paper

Cold-pressed watercolour paper (medium tooth). Photo credit: jacksonsart.com

‘Not’ paper is what I think of as the classic watercolour paper. It is certainly the most popular choice due to the artistic effect created as the paint washes sink into the tooth of the paper, creating a variety of tone which makes it very loose and expressive and great for creating landscapes in particular. Generally speaking the looser your painting style, the rougher the paper texture you’ll likely prefer and if your style is extremely loose then you may prefer ‘Rough’ paper, as below.

Wash on cold-press watercolour paper

‘Rough’ paper

Rough – or even Extra Rough – paper is like an even grainier version of Not paper. The felt that the pulp is rolled through is very rough, allowing deep pits to be created between the pulp fibres and result in a granula-looking  effect. The textural effects this surface encourages in the paint washes make sit particularly suited to landscape painting or to working in bold expressive strokes. It would be very hard to complete a detailed portrait painting on Rough paper.

Rough watercolour paper

Rough-pressed watercolour paper (coarse tooth). Photo credit: jacksonsart.com

As a general note, remember that there isn’t an industry standard for the degree of smoothness or graininess of Hot, Not or Rough paper and it will vary considerably between different manufacturers. When buying watercolour paper for the first time, it may therefore be helpful to visit an art shop in person rather than buying online so you can compare the surfaces and decide which you prefer. Some online art stores will offer the option to buy cheap samples of their loose sheets of paper. It took me a bit of experimentation before I found my favourite type of paper and as we’ll discover, texture isn’t the only factor.

THE WEIGHT OF THE PAPER

This is very important for watercolour paper because of the way that paper will buckle or cockle when watery paint is applied to it unless it’s of sufficient thickness and has been correctly prepared.

Where it is sold in large loose sheets, the weight of watercolour paper for sale will vary. Buying loose sheets is therefore something I’d only recommend once you have a little bit of experience with watercolours. If you buy a sheet of paper with a weight of under 300 grams per square metre it will need stretching in order to prevent it from buckling which is a complication that a beginner can do without! In the US, 300 gsm is equivalent to 140 lb (most art stores will list both the gsm and the lb weight)

If you do want to start painting on loose sheets – maybe because you want to do a very large painting – then make sure your paper is at least 300 gsm in weight or higher. You can actually buy individual sheets that are much thicker than this although confusingly at the higher weights they tend to be listed in lbs rather than gsm. They are also fairly expensive. You could also go for a ‘Watercolour Board’ which consist of a sheet of Hot, Not or Rough paper mounted on to a rigid card. These are up to three millimetres thick (1/8 inch) and don’t require any stretching.

Watercolour board

Watercolour board. Photo credit: jacksonsart.com

Buying watercolour paper in either a  gummed pad or a ‘block’ is probably the safest route for a beginner as these will always be made with a standard 300gsm weight paper. Let’s look at these options now.

FORMATS FOR BUYING PAPER

Watercolour paper is sold as loose sheets or cut from a roll in an art store, or in glued pads, or gummed ‘blocks’. Sometimes you can also buy packets with a number of loose pieces of small size sheets

Loose paper sheets

Loose paper is sold in large sheets (which you can ask an art store to cut down for you) or cut off a roll. Aimed more at professionals or experienced artists loose paper is usually high quality and handmade or mould-made rather than machine-made – more on this below. Many online art shops will allow you to order small paper samples of their loose sheet paper, like these.

Loose watercolour paper samples

A word about paper sizes before we move on to other formats because here again, the lack of industry standards can make things confusing. Loose leaf paper, gummed pads and blocks may all be sold in either Imperial (inches) or Metric (centimetre) sizes, depending on the manufacturer.

When watercolour paper is sold is sold in loose leaf sheets cut to metric sizes these usually do NOT equate to the European A size system (A4, A3 etc). Instead many ranges will sell paper as either ‘Full Sheets’, ‘Half Sheets’ or ‘Quarter Sheets’.  A full sheet is also known as Full Imperial and is 30 × 22 inches, which is a little smaller than the European A1 size. A Half sheet will be 15 x 22 inches, and a Quarter sheet 15 x 11 inches.

Sometimes loose paper is simply sold by the inch instead, the most commonly offered sizes being either 30 x 22 inches or the smaller 16 x 20 inches. Paper sold in metric measurements generally comes in a wider variety of sizes including a common size of 55 x 76 cm which very roughly equates to a Full Imperial sheet.

Glued pads

When paper is sold in a pad it will always be gummed together on the ‘short’ end. Sometimes they come spiral-bound rather than gummed. Glued pads are typically what beginners will start with and are more economical than buying paper in single sheets or in a block. They are ideal for practising with and vary from cheaper ranges made with wood pulp, to the more expensive cotton fibre paper. We’ll discuss these distinctions further down.

Gummed pad for watercolour painting

Gummed pads can be sold in either in Imperial sizes in Metric sizes, or in Metric sizes which conform to the A4 and A3 formats. Usually the more expensive the paper, the more likely it will be available in Imperial measurements rather than ‘A’ sizes. For example Daler-Rowney’s ‘Langton Prestige’ watercolour pads are sold in a variety of inch sizes whilst their cheaper ‘Langton’ range are sold in A4 and A3 sized pads.

Blocks

Blocks are usually made with the higher quality cotton fibre paper. They are available in Hot or Not finishes, but not often in Rough because it’s more difficult to bind. The point of buying paper in a block is the way that all the sheets are fixed to each other to keep them entirely flat whilst you work on them. The sides of the paper pad are coated with a black glue that holds them together all the way around, apart from a small area within the top edge of the pad where there is a break in the binding.

Watercolour block

To use a block, you open your pad and make your first painting on the top sheet of paper. It may look like it’s buckling or cockling a little whilst the paper is wet but once the paint has dried your paper shrink back and will appear completely flat again. When you’re finished you use a palette knife (a kitchen knife with a bit of bend in it would work for this too, but not a rigid knife, or you could also use a credit card!) insert it into the break in the gummed covering and lever your painting off the block. Then you start your next painting on the sheet below, which becomes the top sheet.

Watercolour block instructions
Taking a sheet from a watercolour block

Blocks may be produced in either Imperial or Metric measurements but rarely conform to A3 or A4 sizes, in the latter case. They are most likely to be used by professionals, who tend to believe that A4 and A3 are a little displeasingly ‘letter box’ shaped (however if you actually are seeking a really wide format paper to paint panoramic landscapes on then Arches make a 6×12 inch, very rectangular shaped block that you might like.)

STRETCHING

This guide is really aimed at beginners who are trying to work out what sort of paper to buy, and as already mentioned I would suggest avoiding buying loose leaf paper that’s less than 300 gsm. This is particularly important because big sheets will buckle the most when washes are applied to them. If you are using a thinner paper you’ll need to stretch it yourself, a process involving soaking the paper in water for a few minutes and then using gummed paper to stick it to a flat board such as a sheet of MDF or a purpose made wooden board available from an art shop. If you do want to do this there are plenty of tutorials online that will describe the process for you. Alternatively there are ‘paper stretchers’ available from art stores which will clamp your wetted paper down for you.

Jackson’s smooth panel wooden art board. Photo credit: jacksonsart.com

It’s often said that a paper of 300gsm or above won’t buckle but in fact I don’t find this to be entirely true which is why I prefer to buy blocks so that my paper is conveniently held flat. If I am using paper from a pad or loose sheets then even at 300sgm I find that a slight buckle may occur if I apply a few washes. Therefore although I don’t bother to wet my loose paper I do like to tape it down to a flat surface using gummed paper strip or low-tac masking tape (this also creates a neat edge around my painting when I remove it afterwards). If I still find my paper isn’t completely straight when it’s dry then leaving it under a few heavy books for a week this will usually flatten it satisfactorily.

PAPER TYPES AND TREATMENTS APPLIED

Let’s now look at how paper is manufactured. Proper watercolour paper is made with one of two materials, cotton or cellulose (wood) pulp

Cotton fibre paper

Paper made from cotton fibres (to which linen fibres may sometimes be added for extra durability) is sometimes also known as ‘rag’. paper. Cotton fibre paper is considered to be professional quality paper due to its strength and conservational qualities, as it has longer, stronger fibres than paper made from wood, is completely acid free and shouldn’t turn yellow and become brittle over the years. Therefore if you want to sell your work commercially then using cotton fibre paper is really a must. Because the fibres are tougher the paper can better withstand erasing of under drawings, multiple paint washes, scrubbing and lifting off of paint without damage to its surface. With some good quality cotton papers you can even remove colour from dried paint by re-wetting it and gently scrubbing with a brush, without the surface quickly becoming fibrous/furry.

‘Wood-free’ or Cellulose pulp

The other, more economical alternative is paper is also made from cellulose wood pulp. In the UK this is confusingly often described as ‘Wood-free’ paper. The name is just a shortening of the term ‘groundwood-free’ which means that the wood pulp was broken down chemically rather than being ground mechanically. We call this ‘mechanical pulp’. The significance of this method of production is that breaking the wood down chemically removes the ‘lignin’ in the cellulose. Lignin is the substance within that holds wood fibres together but it is also responsible for the acid damage that can occur to paper over time and cause it to turn yellow. Removing lignin also strengthens and whitens the paper.

It must be said that whilst the treatments applied to wood-free paper will remove most of the acid, only cotton fibre paper is inherently acid-free. Cellulose pulp also isn’t as durable as cotton fibres and won’t take washes, scrubbing and so on so well. It’s marketed as a beginner or student grade paper though I would suggest that if you can possibly stretch to it then the sooner you start using cotton fibre paper the better.

In the UK paper sheets, pads and blocks will clearly state whether they are made from cotton fibres or wood/celllulose (or ‘Wood-free’). In the US paper made from lignin-free wood is sometimes described as ‘Archival Cellulose’ but most often it simply won’t tell you what it’s made from. This can create a problem because any paper that hasn’t had treatment to remove lignin is very much to be avoided; because it won’t stand the test of time, nor will it contain the anti-fungals that are added to both cotton and Wood-free watercolour paper. However if a range just states that it is ‘acid-free’ this likely indicates that it IS a cellulose-based paper with the lignin removed.

Brightening treatments

Sometimes papers are described as ‘Extra white’ or ‘high white’ which indicates that a little bleach and/or some Titanium Dioxide pigment has been added to the pulp. Be aware that contrary to what you’d expect, extra or high white watercolour paper still isn’t bright white. You will also find better quality papers being described as being ‘Free from OBAs’ which refers to ‘Optical Brightening Agents’ .  These are chemicals which can take invisible ultraviolet light and cause it to fluoresce, thus causing the paper to appear whiter. However they are unstable and quickly lose this whitening effect, meaning that your paper will change its shade in a fairly short space of time. Some cheaper watercolour ranges will use OBAs but won’t always state it…however if they don’t include ‘Free from OBAs’ in their description it is fairly likely that these have been added to the paper.

HAND-MADE, MOULD-MADE OR FOURNDRINIER

There are three methods for manufacturing watercolour paper and here once again we find some slightly confusing terms. Let’s run through the different methods.

Hand-made

Firstly there is ‘Hand-made’ paper and this is the most straightforward. When paper is truly hand made the pulp (usually cotton) is immersed in water and a mesh covered frame and deckle are submerged in the mixture by hand and agitated so that an even layer of the pulp settles on the mesh. It’s then removed, placed on a piece of felt, pressed flat, and dried. Hand-made paper is often thicker than most other types, fairly rough in texture and has four lovely deckled (ragged) edges. However it may not be quite as consistently durable as ‘Mould-made’ paper (see below)

A Frame and Deckle

Mould-made

Secondly there is Mould-made (or Cylinder Mould) paper which sounds like it’s also made by hand but actually involves a mechanised process whereby cotton fibre pulp is lifted from a stainless steel vat by a rotating cylinder which is covered in a wire mesh. The wire-covered cylinder is suspended partly above and partly submerged under the water, and is rotated around in the water to pick up a layer of fibres. The layer of fibres is then deposited onto a rotating roller covered in woollen felt called ‘carrier felt’.

Next the water is pressed out of the pulp and then the sheet is pressed between rollers covered in ‘marking felt’ which gives the paper its texture. For ‘Hot’ paper the rollers will be hot and the felt quite smooth, whereas for ‘Not’ paper the rollers are cold and the felt much rougher.

This way this type of paper is made accounts for the difference in texture you’ll often find in Mould-made paper between one side and the other. The ‘felt’ side is the side where the fibres were in contact with the woolen carrier felt whereas the ‘wire’ side is the side that was in contact with the wire mesh covering the cylinder. With Mould-made paper you’ll usually notice that one side is slightly more textured than the other and this is because you are seeing the ‘felt’ side. You can technically paint onto either but the felt side is considered to be superior whereas on the ‘wire’ side the imprint of the mesh may still be slightly visible even after it’s pressed. Most sheets of loose watercolour paper will carry a maker’s watermark that’s imprinted from a metal seal on the cylinder mould, and the side this mark appears on is considered to be the front.

Fourndrinier paper

If paper doesn’t state that it’s hand-made or mould-made then it will be entirely machine-made paper known as ‘Fourndrinier’ after the machine method used to make it. This is the cheapest and most automated method of producing paper and is generally used for the lowest quality ‘student’ ranges. Here the fibre pulp is pushed onto a moving mesh roller and as it travels along the roller the water is removed and the wood fibres are aligned in the same direction. The paper is then pressed between felts and dried. Because the fibres all end up facing the same way, machine made paper lacks the lovely texture and strength of mould paper and is prone to distortion when wet.

GELATIN SIZING

Nearly all watercolour paper will come already sized with gelatin (there are a few papers sized with starch which you can search out if you’re vegetarian or vegan and would rather avoid animal-based size)  Watercolour paper requires sizing to give it some resistance against the watery washes applied to it and without it would soak them up like blotting paper in an uncontrollable way. As well as the choice of grain of your paper (hot, not, or rough) sizing is a really critical factor in how your paper takes watercolour and whether the edges of the paint ‘bleed’ and appear fuzzy – a characteristic that some artists may like and others may not. It’s very subjective.

Sizing also has a number of other purposes. It helps prevent the paint from cockling the paper, allowing the fibres to sink back into place as they dry and keeping it flat. It helps the paper absorb moisture more evenly creating a more consistent colour within a wash. Because sizing allows more of the paint to dry whilst sitting on top of the paper surface it also results in your colours being more vivid.

The main benefit of sized paper though is that it aids your ability to correct mistakes because when you want to lift off or scrub away an area of paint some of the size scrubs off with it, leaving the paper beneath intact. Size may be applied in either a thin or a heavy layer (known as ‘hard sized’), and the more size is added the less absorbent the paper will be, allowing you to remove some of the paint should you wish to before it has fully soaked into the paper and without destroying its surface.

Paper is really just a lot of tiny fibres stuck together. The more these fibres are agitated by washes, scrubbing, removing paint, the looser these fibres become until they start to compromise the paper’s surface and your paint starts blotching in ways you don’t want it to. Size helps to prevent this.

Sizing can be both ‘Internal’ or ‘External’. External means it’s applied to the paper after it’s been made by soaking it in a gelatin bath (sometimes it will be described as ‘Gelatine Tub sized’), whilst Internal means that gelatin was added to the pulp and water mixture before the pulp was turned into paper. The top quality papers have both internal and external sizing. Internal sizing gives strength and durability and keeps colours from soaking in right to the core and losing their vividness, whilst the external tub sizing gives the paper its initial resistance to the paint. Ideally both are helpful.

Since different types of watercolour paper have different amounts of size applied both internally and externally, they will perform differently. Whereas we have noted that ‘Not’ paper is more absorbent than ‘hot’ paper if you want a textured paper that’s less absorbent there are many types available that are roughly textured BUT have a high tub size, making the paint absorb much more slowly. Really the only way to find one that suits your working method is to experiment with several until you find which you like best.

CONCLUSIONS – What should you buy?

If you are aiming to paint professionally then there’s no question that you need to go for the best archival quality paper, which means cotton fibre and not wood-free. If painting just for pleasure then Wood-free is ok, but you may want to experiment with different papers until you find one with the right amount of sizing for the way you work. Stick to 300gsm paper to make sure your paper won’t buckle if you don’t want to go to the trouble of stretching it yourself. If you can, go for mould made paper and avoid machine made because you’re likely to get better results. Most of all, try as many as you can until you find one that works best for you. People have strong favourites in terms of absorption, colour and so on.

For example the most famous and exalted range of watercolour paper is ‘Aquarelle’ made by French paper mill Arches which is one of the oldest in the world. It ticks every box: cotton paper, mould-made, gelatin sized to the core. It’s made only during certain times of the year because the water from the river used to wash the paper becomes muddy during the winter. It’s very durable and strong, but some people find it to absorbent and prefer something with a harder size like Fabriano’s ‘Artistico’ that allows them to lift paint off more easily. The point is that everyone is different and different papers will suit different artists.

Many companies will make both a cheaper range and a more expensive one, so it’s more a question of choosing a range and not a manufacturer. For instance Daler-Rowney’s standard ‘Langton’ range is a wood-free paper made on a cylinder mould whereas their ‘Langton Prestige’ is a more expensive cotton fibre, also mould-made range. Winsor & Newton make two mould-made ranges: a ‘Classic’ range wood-free paper and a ‘Professional’ cotton fibre paper which is mould-made. Canson’s ‘Moulin de Roy’ is a cotton cylinder mould paper which is internally and externally sized whereas their ‘Heritage L’Aquarelle’ range is externally sized only. A very good manufacturer is St Cuthbert’s Mill who make ranges called ‘Saunders Waterford’ and ‘Bockingford’, both of which are mould-made. The Saunders is a cotton paper whilst the Bockingford is made from wood pulp and is internally sized only.

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