While oil paint and watercolours have been around for centuries, acrylic paint is a relatively new medium, being invented in the 20th century. It is a product of the plastics industry: pigment is suspended in a synthetic resin which is emulsified in water. Acrylic paint is very similar to oil paint in many ways, but is easier to use and cheaper, so it is the perfect medium for a beginner. It is also extremely flexible in the ways it can be used, making it a suitable tool for professional artists.

Features of Acrylic Paint

• When undiluted, acrylic paint is completely opaque. Any colour can be painted on top of any other, once the base is dry, without the base colour showing through. You can paint black on top of white or white on top of black with equal ease. This means that you can add details to a picture and correct mistakes once the original paint is dry, re-working a picture as often as necessary to get it right.

• Quick drying: acrylic paint dries very quickly, usually within about 15 minutes. This is both an advantage and a disadvantage. It is possible to work very quickly, churning out a 'masterpiece' in a couple of hours rather than the weeks that it takes to produce an oil painting. On the other hand, it is essential that you work quickly and this might not suit everyone.

• Additives known as retardants can be added to the paint to slow down the drying process, but they tend to reduce the adhesive properties of the paint and can prevent it from drying altogether if overdone.

• Water-based: acrylic brushes can be cleaned with water before the paint has dried, so no expensive, smelly or even possibly toxic cleaning fluids are needed. You can also dilute the paint with water to make it go further, although this will make it start to become transparent. In extremely dilute form, it can be used like watercolour.

• Waterproof: acrylic paint is waterproof once it is dry. Artist-quality paint is not really suitable for exterior use; special exterior acrylic is available which has extra resin in it to guard against the elements. This is great for painting murals in children's playgrounds. It's also great for painting scenery in theatrical productions, as the flats can be stored, then brought out months or years later, washed down and used.

• Dries flat: unlike oil paints, which can be built up into very thick layers, acrylic paint tends become very flat when it is dry, so the Jack B Yeats or Vincent Van Gogh textures provided by 3D paint are not really practical. If you really want a lumpy painting, special 'texturiser' additives are available which will make the paint thicker and allow you to use these effects.

• As the paint dries, it darkens slightly, so you must take this into account when colour-mixing.

Removing Acrylic Paint

Before describing how to put acrylic paint on, it is worth mentioning how to get it off.

• It can be removed easily from most hard shiny surfaces, such as glass or metal, by scratching or peeling. This means it can be used for temporary paintings on windows.

• It is very difficult to remove from clothes and fabric - since the paint is water-soluble until it dries, the affected area should be kept wet and then the fabric should be washed. Once the paint has dried, it is well nigh impossible to remove, although some of it can be peeled off. Acrylic paint sticks so well to fabric that it is sometimes used for painting designs on T-shirts.

• It is impossible to get acrylic paint off nail varnish. The paint and the varnish bond together. So if you wear nail varnish, you might consider wearing thin rubber gloves when painting.

What to Paint on

Acrylic paint can be used on just about any surface, but it adheres best to a surface with a slight texture to it. Canvas and textured paper are probably best, but you can paint directly onto hardboard or walls if you wish. Don't paint onto fresh plaster, as it will absorb all of the water from the paint and make it dry too quickly; apply a base coat of emulsion paint first.

Equipment you will need

Palette

Because acrylic paint dries so quickly, a special palette is recommended which holds water on a dampened sheet covered by a sheet of greaseproof paper. If you don't want to pay for one of these, you can make your own with a dinner plate, some dampened kitchen towels (paper towels), some greaseproof paper and some sticky tape. Better still, if you use a plastic lunchbox instead of a plate, the lid can be closed and the paint will stay workable overnight.

Brushes

Acrylic brushes have stiffer bristles than watercolour brushes. The best brushes for acrylic paint have synthetic bristles rather than natural hair. You'll need one about 1cm wide and a very small one for detail to start off.

Paints

A basic kit of acrylic paints should include the following. Most other colours can be mixed from these:

As you get more proficient you can add:

• Cobalt Blue
• Yellow Ochre (a dirty yellow)
• Raw Sienna (a light brown)
• Burnt Sienna (a medium reddish-brown)

Other Equipment

• Water - in a jamjar or bowl - this is essential for washing the brushes and for diluting the paint.
• Kitchen towels (paper towels) for mopping up and drying brushes.
• Old clothes - as mentioned already, acrylic paint is virtually impossible to remove from clothes once it has dried. It is inevitable that you will get some on your clothes eventually, no matter how careful you are.
• Pencil for initial sketching.
• Toothbrush for spray-painting. Any old toothbrush will do.
• Newspaper and masking tape for covering portions of the picture.
• Natural sponge for applying paint in a mottled effect.

Techniques

Colour-mixing

The basic rules of paint mixing are that there are three primary colours, red, yellow and blue. All the other colours can be got by mixing these, lightening if necessary by adding white.

Red + Yellow = Orange

Yellow + Blue = Green

Blue + Red = Purple

Red + Yellow + Blue = Black (or more often, a sort of dirty brown)

These rules are summarised in the following diagram:

A good rule is always to add a dark colour to a light one, a little bit at a time, rather than the other way around, because it doesn't need much dark paint to darken a light colour. Although the chart shows blue and yellow making green, you need a lot of yellow and only a small amount of blue.

Any mix of two primary colours can be darkened by adding the third primary colour, and lightened by adding white. In this way, you should be able to make any colour using only one type of red, one type of yellow and one type of blue. In practice, it is better to start off with a few different paints of each type and to pick the one closest to the colour you are trying to create.

White added to black gives shades of grey. If you run out of black paint, a good black can be mixed using ultramarine (a dark blue) and burnt umber (a dark brown).

Base Layer

It is good practice to apply a base layer of one colour onto which all other colours are added. There are two reasons for doing this. Firstly, acrylic paint spreads better on top of a base layer than on top of paper, giving you more control as you add colours. Secondly, you can leave gaps in the paint and let the base layer show through in places. With a dark base layer, this is a good way of putting shading effects onto an object.

If you are painting a landscape, you could sketch in the horizon with a pencil, then apply a dark blue to everything above this and a dark brown to everything below it.

Since acrylics are opaque, it is as easy to paint light colours on a dark background as dark colours on a light background. So a base layer of black is quite a popular choice.

Normal Painting

Use plenty of paint on a wide brush and not much water. If you want narrow strokes, use the edge of the brush. Clean out the brush in water before proceeding to another colour. Never leave a brush lying with paint on it while you work with another brush, as once the paint dries the brush will be ruined. If you haven't time to clean it, drop it into water and clean it later.

When you are cleaning up at the end of the painting session, a little soap (not detergent) in warm water works wonders for removing any remaining paint from the brushes.

Blending

Acrylic paint will normally produce a completely uniform colour. However, most things you want to paint will vary in colour due to shading. Shading effects can be simulated using blobs of different colours, as in an impressionist painting, but the best way to produce good shading is to blend the paint.

Put a fair amount of the two colours you want on your palette. Between them, build a few different mixes, so that you have about five different colours on the palette blending from one colour to the other. Now start painting quickly, before the paint dries!

You can produce shading effects using the different colours, and if you are quick enough, can even mix the paint on the painting. This can only be done before the paint dries, which means you have about a minute before the blending becomes impractical.

Glazing

Acrylic paint is very good at making large areas all exactly the same colour. This can look very featureless, so often a bit of variation is needed. This can be done by a technique known as glazing. A pale colour such as yellow or white is very much diluted so that it is almost completely transparent. This is then painted over the dry paint. This technique can be repeated as often as necessary, the glaze getting slightly stronger each time another layer is added.

Scumbling

Scumbling is another way of getting away from the uniform flat colours so easy to produce with acrylics. A completely dry brush is used to apply a very thin uneven layer of paint on top of another colour. This will produce a blotchy effect.

Speckling

A toothbrush can be used to spray paint in dots onto the page to produce a speckled effect. This is suitable for a textured area such as a pebbled beach. Cover over all the areas you don't want sprayed using newspaper and masking tape. Mix up the colour you want with lots of water to make it very dilute. Dip the toothbrush in it, then zip your finger along the bristles, splashing drops of paint on the paper. This is a pretty messy technique and you'll probably end up with paint everywhere, so be careful!

Summary

Acrylic paint is a great medium for the beginner, requiring neither the skill of watercolours nor the patience necessary for oil paints. Yet it is flexible enough that it is also the medium of choice for many professional artists.