I am going to include gouache under watercolors because to be fair, I’ve done a lot more painting with gouache than I have with traditional watercolors. Gouache is basically watercolor that is modified to be opaque. It is made to be opaque by adding a white pigment such as chalk. It’s nothing like acrylic because gouache uses gum arabic as the binder, which is also the same binder used in watercolor paints.
Gum arabic is a natural gum made of hardened sap taken from two species of the acacia tree. It is also also known as acacia gum. Colored pigment is suspended in gum arabic to create watercolor paints. Gum arabic is used as the binder in watercolor paints because it is easily dissolved in water.
When I do work in watercolor paints, I use Winsor & Newton brand paints. There is a student grade paint they make called Cotman Water Colour. These paints do not have nearly the same pigment in it so they are less expensive. While you can certainly create a painting with these, you might find that trying to get really deep, brilliant colors difficult because of the smaller pigment load. Even the tubes are smaller compared to the professional grade. However, these paints are really good for doing quick watercolor studies or color roughss and comps for larger paintings.
Winsor & Newton’s Artists’ Water Colours are a professional grade of artist paints. The tubes are thicker and these paints pack some serious pigment load. These paints offer both great tinting and covering power. Yes, even watercolors can be used opaquely if done right. Keep in mind, some colors make better tints than others. The same can be with respect to those pigments which are suitable for painting opaquely.
Four gouache paints, I’ve used two types over the years and even a third one which I’m not really sure how to classify so I’ll drop it in this category. The first is Winsor & Newton’s Designers Gouache. Fine artists, designers, and illustrators use this brand as well. The comic book illustrator Alex Ross is known for his powerful, iconic images of Batman, Superman, Spider-Man and the X-Men and he paints using gouache.
I have also found Holbein Artists’ Gouache to be a really nice brand to use. If I could describe their gouache paints, I would call them ‘meatier’ (if even such a description makes sense.) They also seem to have a longer shelf life when compared to the Designers Gouache. Keep in mind if watercolor or gouache paints sit for too long without being used, then the gum arabic will tend to harden and you are left with what feels like a rock hard paint tube. I have read online where such paint can be revived. You could try dropping a little water inside the tube and closing it tightly then massage the tube to see if the hardened paint will soften up again. Or, some people have claimed to cut open the paint tube with an Exacto blade and lift the chunks of paint and re-wet them. Remember, watercolor paints can be re-wet and used even after drying hard. So in theory, there is never an end to their life.
A third type of watercolor paint I have used is Chroma’s Jo Sonja Artists’ Colours (called an acrylic gouache). They are a flow formula acrylic that are highly opaque and have excellent covering power. I categorize them as a gouache because they have a beautiful velvet matte finish. And when dry, they feel and look just like gouache. This type of paint is really popular for surfaces other than paper as well. It can be used on wood, terra cotta, metal, fabric, ceramics, glass and some plastics.
I’ve enjoyed using this paint because it seems to combine the best of both acrylics and gouache paints. It is water soluble and flows very much like gouache. However, once it dries, it cannot be re-wetted to work again. So it has the permanence of regular acrylic paint. This works well with my painting style because I like to build up paintings in successive layers and the last thing I want to worry about is a bottom layer of paint being disrupted by a new layer I’m painting right above it. In this way the acrylic gouache similar to regular acrylics but with the added benefit of a matte finish.