For those new to painting, it can be tricky to know the differences between different mediums. Gouache and watercolour paints may look similar at first glance, but they have distinctive qualities that set them apart. Differences in opacity, transparency, texture, and permanence help set them apart.

Watercolour is a transparent medium that tends to be more fluid, while gouache is an opaque medium with a much thicker consistency. Watercolour paints are known for their soft, delicate washes of colour while gouache offers bright, heavy pigment coverage when applied. Because gouache has larger pigment particles than watercolour, it is more opaque. Oftentimes, chalk is added to gouache to create even more opacity.

On the other hand, watercolour is a translucent paint, meaning it will allow some of the colour underneath to show through. Plus, since watercolour is translucent, the textural grain of the paper will show through the paint, which is not the case with gouache.

Gouache has a thicker texture than watercolour, with more solid coverage when applied. In contrast, watercolour is thinner and can be layered to create a more subtle effect.

How does the application of gouache and watercolour differ?

• To achieve a lighter tint with gouache, simply add white gouache to your paint colour. On the other hand, when lightening watercolour paint, you will need to add water to lighten the colour value.

• When working with gouache, its opaque nature allows you to paint light over dark or dark over light. However, with watercolour, which is transparent, you can only paint dark over light.

• It is easy to blend watercolour paint. Blending gouache is more difficult. The colours don’t blend into one another when they touch the way that watercolour paints do.

• Watercolour paint requires a higher water-to-paint ratio, whereas it is best to use a lower water-to-paint ratio for gouache painting.

• In terms of their application, gouache is more commonly used for illustrative works due to its opacity and texture.

Can you use gouache and watercolour on the same painting?

It is possible to use gouache and watercolour together in a painting, but it is recommended to apply gouache towards the end of the painting process due to its reactivity with water. Also, as I mentioned, gouache is an opaque medium that can cover watercolour, whereas watercolour is transparent and cannot cover gouache.

A final tip: if you want to work with watercolour and gouache on the same painting it’s a good idea to have them on seperate palettes because gouache will muddy your watercolour pigments.

Though both mediums can be used in a variety of ways, understanding the differences between them will help you decide which one is best for your project.

Happy painting and I hope you can opaque it until you make it!

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