Use acrylic and poster (opaque) paint, including flat opaque colour, layering light over dark, building from thin to thick, using texture and impasto, and exploiting the fast drying time and water-based handling

What this dot point is asking

SEAB wants you to use acrylic and poster paint: opaque, water-based media, and to understand how their cover, speed and handling differ from transparent watercolour. You should be able to lay flat opaque colour, layer light over dark, build from thin to thick, create texture and impasto, and exploit the fast drying time. These are the most common opaque painting media in the course. The central insight is that opaque paint covers what is beneath, which reverses watercolour's rules: you can paint light over dark, add highlights last, build in layers, and correct mistakes, so the medium rewards a layered, buildable approach.

The answer

How opaque, water-based paint behaves

Acrylic and poster paint are opaque, meaning a layer of paint covers what is beneath rather than letting it show through. This is the opposite of transparent watercolour. Both are water-based, so they thin and clean up with water, but they dry to a water-resistant film. The opacity is the defining property: because paint covers, you can lay a light colour over a dark one, which frees the whole working method. Acrylic is durable and flexible and sticks to many surfaces; poster paint is cheaper, more matte and chalky, and good for bold flat colour.

Flat opaque colour and layering light over dark

Opaque paint excels at flat, even areas of solid colour, ideal for bold graphic work and clear shapes. Because it covers, you can layer freely: paint a dark area first, then add lighter colour and highlights on top at the end. This means an artist can block in the whole image in mid-tones, then build both shadows and highlights, adjusting as they go, and simply paint over any mistakes once dry. It is a forgiving, buildable way of working that watercolour does not allow.

Building thin to thick, texture and impasto

A common approach is to work from thin to thick: start with thin, slightly diluted paint to block in the main areas (the underpainting), then build up with thicker, more opaque paint for detail and the final layers. Acrylic in particular can be used thickly as impasto, paint applied so thickly it stands off the surface in ridges, creating actual texture that catches real light and records the gesture of the brush or knife. Texture can also be built with the brush, a knife, or added materials, exploiting the body of the paint.

Exploiting fast drying and water-based handling

Acrylic dries fast, within minutes, which shapes how it is used. The advantage is speed: you can layer one colour over another almost immediately, build glazes and texture quickly, and corrections dry fast. The disadvantage is that it dries too quickly for the extended wet blending possible in slow-drying oil, so soft gradations on the surface are harder and must be worked quickly or built up in layers. The fast drying also means managing the palette and brushes so the paint does not dry on them. Used well, the speed suits a confident, layered, building approach.

Examples in context

Example 1. A bold flat poster. A graphic poster painted in poster paint or acrylic relies on flat, opaque areas of solid colour with crisp edges, building light shapes over dark backgrounds and adding bright details last. It shows opaque paint used for clarity and impact, where the covering power lets the design read boldly from a distance.

Example 2. Heavily textured modern painting. Many modern painters loaded acrylic or oil thickly as impasto so the surface stands off the canvas in ridges, as famously seen in the heavily worked surfaces associated with Van Gogh. The thick opaque paint records the gesture of the hand and catches real light, demonstrating how the body of opaque paint becomes part of the work's energy.

Try this

Q1. What is the key difference between opaque paint and transparent watercolour? [2 marks]

• Cue. Opaque paint (acrylic, poster paint) covers what is beneath, so light can be painted over dark; transparent watercolour lets the paper and underlayers show through, so lights must come from reserved paper and it is worked light to dark.

Q2. Give one advantage and one disadvantage of acrylic's fast drying time. [2 marks]

• Cue. Advantage: you can quickly layer colours and build texture without waiting, and corrections dry fast. Disadvantage: it dries too fast for extended wet blending, so soft gradations are harder, and paint dries on the palette and brushes.

Q3. Describe how an artist might build a painting from thin to thick in acrylic. [3 marks]

• Cue. Start with thin, diluted paint to block in the main flat areas (an underpainting), let it dry, then build up with thicker, more opaque paint for the form, detail and final layers, adding the brightest highlights and any impasto texture last.