The Difference Between Acrylic, Oils and Watercolor
I like to think of acrylic, oil and watercolor as the BIG THREE paint mediums. There are other ones but if you're thinking about painting you'll probably start with one of these. I get a lot of questions about these three, and there understandably seems to be some confusion about the differences between them. So I'm going to break it down in this article!
First: all paint is made with a pigment (the color) and a binder to hold it together. The binder is what differentiates the colors.
OIL
I'll start with the oldest on the list, oil. Oil has, you guessed it, an oil based binder. You'll need a primed canvas or board to paint on. You'll also need a solvent to thin the paint and clean your brushes. They can be smelly and hard to clean up. You'll want a dedicated spot to keep your oil supplies, paintings in progress and solvents.
Because the solvents and binder will eat through paper or other supports, you'll need a primed canvas or board (traditionally with a white primer called gesso.) If you don't have a primer, you can run into problems with raw canvas or wood because of chemicals that can leech into the painting and vice versa.
Oils are "workable" because they take a long time to dry--days, weeks or even months. Fully dried, they are highly archival and durable. Artists have been using oil paint for at least 500 years, probably more. Pretty much any painting in a museum from before 1950 was made in oil.
I painted in oils for many years during my "realism" phase.
You can work in thin glazes, or you can work in impasto, which means thick, dimensional paint. This style takes a LONG time to dry. Fun fact, before aluminum tubes were invented, artists usually had to make their own paint, and they typically stored their fresh paint in pig bladders!
ACRYLIC
Acrylic is the comer to our little pack. Invented in the 1950s, it's made of a water based plastic polymer resin. What does this mean for you? It thins with water, it dries quickly, it's mostly odorless, and straightforward to use. It dries very quickly, thinly applied it will dry in minutes. In an impasto style, it will dry in a few days and have a permanent, rubbery feel to it, like plastic. Because, it IS plastic. You can use it thinly, almost like watercolor, or thickly, like impasto. Most acrylic right out of the tube will be semi-transparent. Like oil, you can let the lower layers dry and then paint some more, indefinitely. You can thin the colors down and use them almost like watercolor. A benefit to acrylic is you can paint on anything, like paper, board, canvas or matt board. When the colors dry, they are permanent, including on your jeans.
Acrylics come in various viscosities--you can get liquid acrylic right on up to heavy body, and you can mix various mediums into it. I like either the liquid type, which is kind of like watercolor, or the super thick heavy body stuff which I mix with a extra firm gel medium so I can really build up the volume.
WATERCOLOR
Watercolors use a binder called gum arabic, and also occasionally things like honey. They are water soluble, and they come in two forms--pans or tubes. The pans are dry cakes that can be activated by water. The tubes are gel like, and can be used straight from the tube, or dried onto a palette and reactivated with water as needed (my favorite method).
Watercolors are typically used flat on paper, and they are transparent. I like to think of watercolors as transparent layers, or veils. The paper type and quality is important with watercolor as the paper will strongly effects the drying and painting process. Watercolor is always water soluble, so even after it has dried, you can lift it with a wet brush. You can do multiple layers with watercolor (the veils). Problems emerge if you have improper paper: it will pill and buckle. Even with good watercolor, thick paper there's a limit to how many layers you want to add before things get muddy.
If you're interested in some awesome templates (designed for watercolors but they would work for acrylics too)--you can grab them here!
There are tons of other mediums for painting: Gouache, marbling, liquid acrylic, india ink, tempera, water based oil, soft pastel, impasto, spray paint, enamel, resin, alcohol ink, encaustic, watercolor pencils, and MORE!