A Brief Guide to watercolour materials

Posted by Jeff Rowley on

Watercolour paints

Are a translucent medium that consist mainly of pure natural or synthetic colour pigment mixed with Gum Arabic. It is supplied in either tubes or pans (solid blocks of colour), when mixed with water the colour spreads easily onto paper.

Watercolour painting can be a relatively inexpensive way of starting to paint with lots of resources, in the forms of books, courses, videos and on-line content available to help those starting out. It is also highly portable if desired, lending itself to working outside or producing sketches.

There isn’t really any other medium that matches the delicate luminosity of transparent watercolour. Although painting with watercolours can be difficult to master with its fluid nature making it hard to control and mistakes can be difficult to correct, but it is exactly these very qualities that makes the medium so popular.

Gum Arabic is a naturally occurring substance, used for its ability to dissolve easily in water keeping the pigment even and moist. It is non-toxic, made from the sap of the Acacia tree, a natural glue that helps the pigment to stick to the paper. Gum Arabic can also be bought separately used as a medium for slowing down the paint drying time.

Watercolour is a semi-transparent medium, with some colours are more opaque than others, the ‘proper’ way to achieve areas of pure white this is done by not painting the paper where white is required usually masking off areas first with masking fluid, tape or wax resist sticks being useful tools for this. Whites are available, (more info here) for either producing opaque pastel shades or for highlighting onto top of dried layers or for non-white backgrounds. Rather than using white to lighten a colour as you would with other paint types, colours are best lightened by thinning with more water.

Both Pans and Tubes of watercolour are made with the same pigments and Gum Arabic so are completely intermixable, so why use one over another? Sometimes the choice can be down to personal preference, but both have their own advantages and disadvantages;


• Easier get strong, rich colours
• Kinder and less wearing to paintbrushes
• Precise amount of colour can be used
• Tubes can split or lids get stuck on


• Easy to transport, great for travelling.
• Neater to store
• Good for light washes
• Less easy to get strong colour.
• Very wearing on brushes.

‘Artist’ or ‘Professional’ quality colours offer a larger range of colours and use the best quality pigments, which is why the prices are split into ‘series’ that reflects the cost of the raw materials used to make the pigment.

‘Student’ quality, for example Winsor & Newton’s Cotman or Daler Rowneys Artfine, use either less pigment and more fillers or a synthetic (or hue) version of a natural pigment and as a result are priced at a single standard price and offer less colour choices. They are popular for people starting out or where large quantities of colour are required.

The type of pigment can also have an impact on a colours permanence (i.e. it may fade in sunlight), manufacturers will give a level of permanence on each of the packaging and on colour charts.


Like other types of paints manufacturers offer mediums or additives to change the formulation for adding effects to your paintings.

Already mentioned Gum Arabic slows drying, increases gloss & transparency, controls the spread of wet colour and reduces staining.

Ox Gall Liquid by adding 3-4 drops per cup of water and mixing directly with Watercolours it will increase wetting and improve flow and t can also be used to reduce surface tension for use on very hard sized papers.

As well as standard removable masking fluid, available in off-white, white or blue (dependant on manufacturer) in addition Winsor and Newton produces a permanent version. It is applied by brush, colour shaper or ruling pen or some come with applicator bottles, 

Aquapasto is a translucent gel medium when added to Watercolours or Gouache reduces the flow and thickens to allow an impasto effect to be created.

Texture Medium can be applied directly to paper or mixed with Watercolours, this medium contains small particles that add a fine texture to watercolour paintings and can be used to give the impression of depth and structure.

Lifting Solution, by it applying directly to paper and allowing to dry before use, it allows dry colour washes, including staining colours, to be easily lifted from paper with a wet brush or rag, ideal for making corrections.

Granulation Medium, gives a mottled appearance to colours which usually have a smooth wash

Blending Medium, is used for slowing the drying of Watercolours, allowing more time for blending, especially useful in hot temperatures.

Other non- specific mediums such as bleach or alcohol are often employed to create effects too.


Gouache is sometimes called 'Designer's Gouache' as before the wide spread use of computer graphics programs, it was the first choice for commercial artists. Gouache is simply a form of watercolour with added body colour, making it opaque. It is of a similar formulation and compatible with modern transparent watercolours, but won’t give the same effect.

Gouache then is used to create areas of flat, opaque colour that can be painted quite easily, allowing light colours to be painted over dark if necessary, although not perhaps with the same clarity as acrylics. A Gouache painting appears chalky, like a high quality poster paint, with a very matt finish. It is best as a medium in its own right, or with watercolour for a mixed media effect, but when mixed with Watercolours perhaps to lighten or darken colours transparency will most likely be lost.


Good brushes are indispensable watercolour supplies. Even for those just starting out, high-quality brushes are a great investment and will last a long time with proper care. Working with inadequate brushes can be frustrating, using good brushes makes learning new watercolour painting techniques much easier.

Good watercolour brushes are made with either natural or synthetic fibres. Sable brushes have a spring that makes them very responsive to the users hand, Kolinksy Sable are generally considered to be the very best (and most expensive) natural-hair brushes, Red Sable offer an excellent quality at a lesser price. Developments in Synthetic brushes mean they rival the quality of sable and are more durable, so offer good value.

A little like dress sizes, brush sizes differ from brand to brand, so a size 0 in one make may be closer to a size 1 or 2 in another.

Brush Shapes

• Round: The hairs form a round tip; these brushes are the most common and most useful because they can make lines as well as broad strokes. They’re graded by size, No.’s. 00000 to 24

• Flat: The tip has a straight edge that produces an angular stroke. These are ideal for laying down large areas of even colour and defining precise edges. Sizes are measured in inches along the flat edge.

• Wash: These large, flat brushes can hold a lot of paint, allowing the artist to lay large washes.

• Liner: A small round brush with a pointed tip is good for making fine, thin lines and for signing a finished painting.

• Mop: A large, round brush made with soft hairs can hold a lot of water when wet or soak up a lot of water when thirsty. A mop is useful for wetting large areas of paper or blotting or blending paint that is already applied.

• Rigger: This brush has very long, thin hairs that come to a precise point; it renders very fine, long lines. It gets its name from originally being used to paint ships rigging.

• Hake: This wide, flat brush has a flat handle and is useful for laying down large washes.

Brush Care

Don’t let brushes rest bristle-down in water for any length of time.
Rinse in cold water after use.
Shake out excess water and shape with fingers; dry lying flat.
Store brushes bristles-up in a jar.

Paper (more information here)

Watercolour paper comes in a variety of thicknesses and textures a good paper is made from 100-percent cotton rag, though some artists do prefer synthetic paper. Less expensive papers will use a cotton/wood mix or be 100% chemically treated pulp. Thickness is indicated by weight, given in grams per square meter (gsm) or pounds per ream (lb). Standard weights are 150 gsm/72 lb, 190 gsm/90 lb, 300 gsm/140 lb, 356 gsm/260 lb and 638 gsm/300 lb.

The lighter the weight of the paper it is more likely that the paper will ‘cockle’ or buckle when a lot of water has been used, one way to overcome this is to stretch your paper.

The characteristics of watercolour paper, such as whiteness and texture, differ by manufacturer; sampling the various watercolour papers and sketchbooks is recommended.

Hot-pressed (HP, Smooth) paper is run through hot rollers that flatten the surface and create a smooth, finely grained texture with almost no tooth. It’s less absorbent, so pigments look brighter on the surface. Botanical paper is extremely smooth and white ideal for fine detail work.

NOT or Cold-pressed (CP) paper is pressed flat between felt sheets and has a distinct texture or tooth; it is the most versatile and popular paper.

Rough paper is not pressed during manufacturing and has a prominent tooth that lets pigment particles settle in the indentations, creating a grainy texture.

Synthetic paper is water-resistant, so it won’t buckle. Made of polypropylene, it has an extremely smooth surface.

Useful tools

• Palettes: There are many different styles of palettes for watercolours, ideally they need to be flat, white and impervious to water. Rectangular shaped ones are popular with wells for holding colours and separate mixing areas. Watercolour pan sets will often include a fold out palette.

• Water containers: These are best to be made from unbreakable materials with wide mouths. It is useful to have at least two in use, one for water to dilute the paint and one for washing out the brushes while working.

• Pencils, for preliminary drawing.

• Masking fluid and tape: These let you preserve the white of the paper.

• Sponges: Use a sponge to soak up excess water from brushes or to moisten the paper and create textures in wet paint.

• Scrapers: Manipulate paint on the paper with palette knives, a credit card or even the tips of brush handles.

• Towels and tissues: Dry brushes and blot the paper with these.

• Spray bottle: Use a spritzer to keep paint from drying out on the palette and to create special effects when painting.

Watercolour Pencils & Sticks

As the name suggests, these are pencils made with watercolour pigments. They are very versatile, and can be used dry just like ordinary coloured pencils, but add water, and pigment turns to paint.

There are several ways to use watercolour pencils: They can be applied by sketching areas of colour, then a wet brush drawn across them, to turn them to paint. Alternatively they can be used on wet paper or paint, this will give lines, but with a soft edge. Also use along side watercolour paints.

Watercolour Crystals

The Brusho brand are crystals of pigment that release their colour when mixed with water, they can be used like standard watercolours but are most effective when dropped onto wetted paper or applied and then sparyed with water giving gorgeous, uncontrolled effects.


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