Why is my gouache not opaque? 

Many artists find it difficult to achieve the desired level of opacity in their gouache painting, which can be frustrating. There are several reasons why your gouache paint is not opaque: the quality of pigments, the amount of water, the type of paper, and the opacity of pigments. 

Table of Contents

Check the quality of pigments

One important factor that affects the opacity of gouache is the quality of pigments used. Cheaper gouache brands may contain fillers or lower-quality pigments that make the paint more transparent, like the Himi gouache. 

If your gouache is less opaque than you’d like, try investing in higher-quality gouache paints that use pure, high-quality pigments. As an art teacher, I always recommend buying the best quality art supplies you can afford. They will help you achieve better results in your paintings, last longer, and save you money in the long run. 

You don’t have to spend too much money. If you get this primary set by Holbein, you’ll have the best quality/price you can find.

Favorite gouache palint
Holbein Gouache Primary set

Use more pigment in the mix

Another way to increase the opacity of your gouache paint is to use more pigment in your mixture. Many artists make the mistake of diluting their gouache paint too much with water, which can make the paint more transparent. If you’re coming from watercolor, this is a very common issue!

I always advise my students to use a higher pigment-to-water ratio in their mixtures to achieve greater opacity. This means using more paint and less water when mixing your gouache. Of course, finding the right balance is essential – you don’t want your paint to be too thick or clumpy. But by using more pigment in your mixtures, you can create a thicker, more opaque layer of paint on your paper. This can be especially helpful when creating bold, solid shapes or blocks in large areas of color. 

You can also decide that you want transparent gouache by adding more water to your mix.

Change your paper

Believe it or not, the type of paper you use can also impact the opacity of your gouache paint. Rough or textured paper can cause the paint to be absorbed more deeply into the fibers, making it appear less opaque. On the other hand, smoother paper can help the gouache sit on the surface more, resulting in a more opaque finish. 

There is no specific paper for gouache, and this video lets you learn how to select the perfect paper for your project. 

If your gouache is less opaque than you’d like it to be, try experimenting with different types of paper and see how it affects your painting. You might be surprised at the difference it can make!

Add a primer

Another option to consider when trying to increase the opacity of your gouache paintings is to add a primer to your paper before painting. A primer is a thin, opaque layer applied to the paper’s surface before painting. This layer can create a more uniform surface and increase the opacity of your paint by preventing the paper from absorbing the paint. 

You can use a white or colored primer, as this will help to enhance the brightness and vibrancy of your paint colors. Several different types of primers are available, including gesso, acrylic primer, and ink.

Garden Paint Challenge
Acrylic primer under the gouache paint

Use an opaque color

When it comes to painting, not all pigments are created equal. Some pigments are naturally more opaque than others, which can make a big difference in the opacity of your paint mixtures. You must check the symbols on your gouache tubes to see which pigments are opaque and transparent. 

Opaque pigments have a filled symbol, and transparent ones are empty. You can learn more about gouache labels here. By selecting opaque pigments for your mixtures, you can increase the opacity of your paint and achieve a more solid, opaque finish. 

White gouache has different levels of opacity as well! I keep Chinese or Zinc white for mixes, which are semi-opaque, but if I need an opaque pastel color, I’ll use Titanium or Permanent white, which are fully opaque. This small step can make a big difference in the overall opacity of your gouache paintings!


In conclusion, achieving the desired opacity level in gouache paint can sometimes be challenging. However, by considering factors such as the quality of pigments, the amount of pigment used in the mixture, the type of paper used, and the use of opaque gouache, you can take steps to enhance the opacity of your gouache paintings. With practice and patience, you can master the art of gouache painting and create beautiful, opaque works of art that you’ll be proud to display. Happy painting!

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