'Gouache is a water-based paint. It contains colour, a solid white pigment such as chalk, a binding agent such as gum arabic and water. It has a great, velvety texture that absorbs light without reflecting it, creating a very smooth, solid appearance,' says Robert Brindley.

'The word gouache roughly translates as ‘body colour’ or ‘opaque watercolour’. As early as the ninth century, Persian artists were using it for painting miniatures; in more recent times it has been widely used commercially for advertising, book illustration, comics and design work.

'Although similar to watercolour in appearance, it dries with a solid, matt finish and the paint becomes absorbed into the paper surface. Some skill is required when overpainting gouache as it is easily disturbed by subsequent washes and layering, even when dry. It is mainly used as an opaque medium and can be used with both watercolour and acrylic.'

Gouache versus watercolour

Gouache, like watercolour, is available in small, very concentrated tubes, or pans; both are diluted by adding water. Although both media consist of the same basic materials, watercolour pigments have very small particles, enabling the paint to be spread thinly and transparently. Gouache has larger particles and more body, making the paint finish matt, denser and more opaque when dry – it dries very quickly, making it ideal for quick, direct painting.

Like watercolour, gouache is easily re-wetted, which is ideal for adjusting edges, etc, with a damp brush. If you want to produce a spontaneous, transparent painting, gouache is probably not for you. However, if you would like to experiment with mark making, bold solid colour, texture and a variety of other effects, you should try gouache.

Gouache versus acrylic

Although they are both essentially opaque media, gouache and acrylic have many differences. Acrylic paint is more durable, the dried paint is waterproof and very stable, so can’t be rewetted and reworked, other than over-painting. Gouache is more forgiving and can be reactivated to make adjustments. Acrylics can be painted on many surfaces, including paper, wood, glass and plastic. Gouache is best suited for painting on paper or primed card.

Acrylic, unlike gouache, can be applied very thickly, with brushes and other tools, to produce heavily-textured surfaces. Gouache is typically only applied with a paintbrush to produce a smooth surface.

Sunset, North Yorkshire Moors, gouache on Arches Not 140lb (300gsm), (15x19cm)

Basic materials for painting in gouache

The paints

I recommend starting with just a few, mainly primary colours, such as the Winsor & Newton introductory set (see below). This will enable you to mix a fairly wide range of hues.

ORDER AN INTRODUCTORY SET HERE

Brushes for gouache

I use the same brushes as I do for watercolour, plus a couple of flats.

There is no need to waste money on expensive brushes such as sables for gouache. I can recommend Escoda Perla Nos. 6, 8, 10 and 12 rounds, a No. 2 Pro Arte Acrylix rigger and a couple of inexpensive flats.

Surfaces

Gouache works well on watercolour paper of reasonable quality, providing it is at least 140lb (300gsm) in weight.

Thick drawing paper, or a good-quality card can also be used; I have also used the reverse side of scraps of mount board. When using card or mount board I always prime both sides with a coat of acrylic white primer.

Mediums

Occasionally, I will use a medium texture paste to provide a little tooth, which adds interest to the paint surface and enhances the brushwork.

Mixing palette

I use three or four ceramic mixing palettes but old plates work very well. Try to use ceramic mixing areas rather than plastic, as they are far superior.

Miscellaneous

Additionally you’ll need a pencil, eraser, paper towel and, of course, water.

Gouache painting techniques

Here are just a few of the many options available to you. As always, you will discover your own way of getting the best out of the medium.

1. Opaque layers: use without adding much water to achieve a rich opaque colour that covers anything underneath it. If you want to allow some of the underpainting to show through, try a dry brush effect. This will be more effective if your paper has a little texture/tooth. These opaque layers can be built up in layers to add, for instance, a mountain over a sky, a building over the mountain, followed by a tree or figure over parts of the building.

2. Wet-on-wet: dampen your paper then introduce wet gouache to achieve soft shapes and blurred edges. Although this method can be a little bit hit-and-miss, with practice you will soon improve your success rate.

3. Dry brushing: this allows you to add texture to your painting. Simply pick up some gouache paint either without or with just a little water, then brush off the surplus paint (use a scrap of paper or paper towel). Quickly sweep the brush across your painting to achieve a hit-and-miss ragged brushmark. Practice will enable you to obtain the desired textural effects.

4. Scumbling: for a rougher, more textured surface, use a large/medium-sized flat to dry brush with a small amount of undiluted colour. Pull the brush over the surface; you will observe random gaps in the stroke that let some of the background colour show through, creating texture. Different textural effects can be made by increasing or decreasing the pressure on the brush.

5. Adjusting and correction: one of the most useful aspects of gouache is that you can rework elements of a painting very easily, such as softening a hard edge by rewetting.

How to paint with gouache

One of the characteristics of gouache is that it dries darker than the colour applied to the painting. Achieving the required colour quickly can be challenging for the beginner but with practice you will be able to adapt your mixes accordingly.

I always tint or colour the surface I work on. This is optional but I find it unifies the entire painting and reduces the number of small, unpainted areas of white paper showing through. This tint can be very diluted gouache or acrylic; I prefer acrylic as it is stable and won’t be disturbed by subsequent layers of paint, but you must do what works best for you.

Gouache is rarely used straight from the tube but a little water is all that is required. Generally, it needs to remain opaque but fairly runny (not uncontrollably so). When you dilute gouache with water, you can apply it as a wash that will dry opaque in most cases. If the wash is very diluted and painted over a strong, existing colour, it may influence the colour, but will not cover it up.

Do remember that gouache is water-soluble and that when you paint over an existing, dry layer you will disturb it, which can result in muddy effects. To reduce this, make sure your background layer is completely dry, then place the new colour as lightly as possible, without the brush damaging the dried colour.

To achieve details and lines, work over opaque, dry, backgrounds. To achieve the most effective results, a dark/detail line laid over a light background, or the reverse, will work best. Similarly, complementary colours, or warm and cool combinations will be effective, too.

Robert's top tips for using gouache:

• Don’t use too much water in your mixes.
• Use less water in each successive layer of colour to lessen the chances of disturbing the under layer.
• Use less pressure on the brush with each layer. The lighter the touch, the less the risk of disturbing the under layers.
• Resist adding detail too early.
• Dried gouache colour is soluble with water, so be careful not to splash or accidentally drip water on to your painting.
• Resist over-painting before the previous layer is absolutely dry.
• Plan your composition meticulously before you start. This will give you the best chance of success.

Demonstration: Snow near Grange, Cumbria

Snow near Grange, Cumbria, gouache, (24x27cm)