Is Water or Medium Better for Glazing with Acrylics?

When applying glazes to acrylic paintings, you have two options: water or a glazing medium. Is there a benefit to using one over the other? Either will work, but there are distinct advantages to choosing a glazing medium.

No matter which base you choose for your acrylic glazes, it's also important that you mix them properly. You do not want to break down your pigment with too much water,​ though a glazing medium can be used in any ratio you desire. Much of this depends on your style of painting and the look you're going for.

The Benefits of a Glazing Medium

Glazing medium is preferred by many acrylic painters because it maintains or adds to the gloss or matte effect of the paint. These mediums are available in both gloss and matte finish. You will want to choose which works best with the paint you're using as well as the effect you desire in the painting.

The other (and more important) advantage to a glazing medium is that it retains the 'stickability' of the paint. The medium contains a binder (or glue) that gives the mixed glaze the ability to stick to the panel or canvas and any underlying layers of paint. Water, on the other hand, can break down the binders that are present in the paint and too much may lead to your paint peeling.

You can use a glazing medium with paint in any proportion, adding as little paint as you like for the effect. This is because the medium is like a thin, colorless paint due to that binder.

The Issues With Water For Glazing

Water works fine for glazing up to a point. As mentioned, you do run the risk of the binder in the paint being diluted too much and losing its ability to stick.

A fifty percent ratio of paint to water is the general rule. Some paint manufacturers suggest no more than 30 percent water. Artists often don't pay too much attention to these recommendations, particularly when it comes to glazing.

You will know when you have too little paint in your water. If the paint lifts off when you paint over a thin layer with a stiff brush, then you've gone too far. It's very similar to how watercolor paints work.

A Mix of Water and Gloss Medium

If you like, you can also use an acrylic gloss medium along with water to create a custom finish while glazing.

• An equal proportion of water and acrylic gloss medium will produce a matte finish.
• As you use a higher percentage of gloss medium, the finish will become more satin-like.
• A straight gloss medium will, of course, produce a glossy finish.

You can vary these finishes anyway you desire for the effect you're going for in the painting. Also, consider using various finishes to bring out specific properties in certain areas. For instance, you might want a high-gloss glaze over a lake in your landscape and more of a matte or satin look for the pine trees. This approach can produce some very nice effects.

As always, if the finish didn't come out exactly as you planned or you don't like the final results, you can always add a varnish. They too are available in matte and gloss.