In the world of art, there is no way these two can be compared. They are two very different materials that produce different forms of art. But given the two, people almost always start out with water colours. Water colours are much easier to use for beginners because they leave room for plenty of mistakes and corrections. Most people will feel comfortable with water colours because of the pigments, animations and illustrations.
What are the main similarities between water colours and acrylics?
One of the main similarities between the two is that they are water soluble paints. It means that they can both be thinned by water and you can rinse out the brush with water when you complete the painting. Neither of them uses harsh chemicals which makes them safe for everyone to use, even the kids. Both are relatively cheap when compared to other painting mediums.
The main differences between water colours and acrylics
As an artist, I have experienced my fair share of water colours and acrylics. All water colours I seem to use have the same type of texture. They are solid but break down immediately you place them in water. Acrylic paints come in different varieties with different viscosity. The heavy viscosity acrylics are named heavy body, light viscosity is known as soft body or fluid and medium viscosity is the paste.
Fluid viscosity is great for realistic painting styles and glazing while the heavier paints are better for impressionistic and impasto styles because they hold on the brushed pretty clearly. A heavy body paint is perfect for people who paint with pallet knifes.
With water colour, the glazed effect is very easy to achieve. The water tends to make the paint transparent like. Achieving an impasto look with water colour is going to be difficult unless you paint of the watercolours several times; the issue with this method is that it ruins the integrity of the paper. If you are looking to achieve an impasto look you might as well go for the acrylic painting. If you already like pain, chances are you will not love the outcome and feel of the water colours. Water colours do not work well with bolder brush strokes as compared to acrylics.
Generally, acrylics are more versatile than water colours. Most water colour paintings are done on paper while most acrylic tend to be done on canvas. It is difficult to show water colour on canvas so that leaves very little options.
How watercolours and acrylics work
Acrylics are great on canvas, but you can also use them on boards and thick paper. Most people use glass pallets without wells because they do not add water to the acrylic. If you are using heavy acrylic, you can add some water to thin it enough and make it medium. When working with water colour, use a spritz bottle to break down the paint. You should expect to use more water here but keep them separated because the paints might mix and ruin the colours. Use a plastic separator to dilute the watercolours and have a water can available to clean the brush for immediate re-use.