When you apply a paint, does it cover the colour underneath in one coat, or does it take several? That property is what we call opacity. Opacity directly affects the quality of the paint, how much of it you'll use and how long the job will take. In this guide we explain what opacity is, what affects it, and how to get the best result.
What is opacity?
Opacity is how well a paint covers the surface or colour beneath it. A high-opacity paint covers the base completely in a few coats; a low-opacity paint stays semi-transparent and lets the colour beneath show through. High opacity = fewer coats, less paint, faster work.
What determines opacity?
- Pigment load: More pigment, and better pigment, means higher opacity. ART IST acrylics are highly pigmented.
- The type of pigment: Some colours are naturally more opaque (many whites and earth tones, for example), others more transparent (some yellows and reds).
- Coat thickness and number: A thin but adequate coat gives the best opacity; a very thin, watery coat stays transparent.
- The base colour: Opacity matters much more when a light colour goes over a dark base.
Transparent and opaque colours
Colours are classified as opaque or transparent. Opaque colours cover in one or two coats; transparent colours let light through and are used for layering and glass-like effects. Both are useful — what matters is knowing what you want. If you want a transparent colour to cover, put a white or opaque coat (a primer) underneath.
Ways to improve opacity
- Use a primer: On dark or patchy bases, a coat of white primer makes the colour above come out vivid and covering.
- Apply thin but adequate coats: Over-thinned paint doesn't cover; thin coats at the right consistency are ideal.
- Let coats dry: A fresh coat over a dry one increases opacity.
- Choose the right colour: If you want single-coat coverage, go for opaque, highly pigmented colours.
- Try the self-varnishing/dense series: Self-Varnishing PLUS offers high coverage in a single coat.
Opacity and cost
A high-opacity paint may look expensive at first, but it's actually economical: fewer coats, less product, less time. A cheap, low-opacity paint takes coat after coat to cover, and you end up spending more. Quality, highly pigmented paint is usually better value in the long run.
Common mistakes
- Over-thinning: The paint turns transparent and won't cover.
- Skipping the primer (on a dark base): Light colours come out washed out and need many coats.
- Applying one thick coat: Runs and marks; several thin coats cover better.
- Assuming a transparent colour is opaque: Check the label or the colour; put white underneath if you need to.
Frequently asked questions
Is there a paint that covers in one coat?
Highly pigmented, opaque colours cover most light bases in one or two coats. For a light colour over a dark base, a primer is still recommended.
Why is my colour coming out washed out?
Usually low opacity, too much water, or a dark base. A primer, the right consistency and thin coats will solve it.
Is opacity the same as durability?
No. Opacity is covering power; durability is the paint's resistance to wear. They're different, although quality paints usually offer both.
Why does white cover so well?
White pigment (usually titanium) is naturally very opaque, which is why it also makes an ideal primer.
What are transparent colours for?
Layering, shadow, stained-glass effects and colour depth; because they let light through, they build rich tones.
Opacity is a key property that affects both the quality of your result and your wallet. Choose a highly pigmented paint, use a primer if needed and work in thin coats — for a full, vivid result with less effort. Take a look at our high-opacity acrylic paints!
