Standard medium for acrylics

Standard medium can be used to improve the flow of the paint or to make your paint more transparant. I will discuss effect mediums and gels another time.

Why don’t just use water instead?

The use of water has two major downsides:

1: Pigments will begin to float; at some part you get more pigments than at other parts (granulation effect). With medium you don’t have this effect: the pigments will be evenly spread.

Difference between using medium and water: top row is diluted with medium, bottom row with water

2: Using too much water will dilute the binder too much. The binder then loses it’s ability to keep the pigments together and to keep them stuck to the canvas. Medium consists of binder, this way you can dilute the paint as much as you like, it won’t have negative effects on the adhesion.

Hey, the medium looks milky!

That’s just normal. Acrylic binder is a bit milky, but when dry it is completely transparant. This is also why (most) acrylics have a colorshift from light to dark: the milky binder dries transparant. Nowadays there are some brands that produce acrylics with hardly any colorshift.

Medium looks milky in its wet form
But it dries completely transparant!

Gloss or matte

Most brands offer the choice between matte or gloss medium. When dry, gloss medium will give a shiny result. Matte will just be the opposite; it will decrease a glossy sheen.

This is all a matter of taste. In general, matte medium resembles the natural finished look of acrylics the most (but keep in mind that some pigments dry more glossy than others).

How to use it?

It’s very easy: treat it as if you are using water. When you want to make you paint more fluid, just add some medium. Of course (just like when you add water) this will make your paint more transparant at the same time.

Just use it the same way as you would do with water!

You can use medium for a more watercolor style of painting. Just add medium like you would add water. To avoid unpleasant surprises, don’t forget to test the transparancy on a scrap of paper!

Test the opacity before you apply it to your best masterwork piece of art!

Sometimes it’s nice to use medium to make a kind of flat wash, as if it’s a watercolor. You can easily put in global color planes, nice to have as base layer for your painting.

In this example I used medium to make a transparant first wash, just to divide the shadow and light parts very globally. This gave me a nice base layer to continue working on.