What is a glaze

Glazing is an incredibly useful painting technique. If you are a painter and not familiar with glazes, you are in for a real treat. You can use it to create a variety of painting effects, fix issues, illuminate color and add the illusion of depth in an artwork. Glazing has been used throughout history by many artists including our beloved painting masters, and is still used today for contemporary styles ranging from realism to abstraction. Glazing can be used with most painting mediums including oil, acrylic and watercolor. It is my number one favorite tool.

So what IS a glaze? Simply, a glaze is a transparent color. It can also be an application of a transparent color on a painting already started. In this article I offer a variety of ways to use and create glazes for painting.
 

When and how to use glazes

A glaze is often applied to a painting while it is still in process, to shift or change whatever colors are already there. It can be applied very subtly to just slightly shift an underlying color, or more strongly to dramatically change underlying colors. In general though, it is usually used OVER a previously applied and dry, layer of one or more colors.

The famous Old Master’s often used a glazing technique called a grisaille meaning grays. First an underpainting of grays or neutrals is applied that indicates where the darks and lights will be. This “gray” underpainting allows the artist to concentrate on patterns of dark and light and general composition concepts, without thinking of color just yet.

When this underpainting is dry, the artist then applies glazes of color over the grays. The color can be applied bright or light, letting the gray underneath shift the hue to be a bit more muted. In this way the gray underpainting turns into a colored painting containing a variety of values or tones.

There are many ways to create underpaintings, and the use of grisaille is a great way to add the look of an Old Master’s realism. As an abstract artist, I like to apply bright opaque areas of color as my underpainting and then use glazes over those to shift tone and hue. This contemporary use of glazing has many advantages. Glazing can create shadows under forms for the illusion of 3D. It can also allow for shifting lights and darks, which can change a flat colored form into the feeling of volume or 3D shape.

Why glaze

Painters often use whatever technique easily gets the desired result. If you want to completely cover over an area or drastically change a color, you would paint over it using an opaque paint application. If, however, you don’t need to substantially change something on your painting, but instead want to add some small shifts or nuance of color, then a glaze is your answer. For example, let’s say you are painting a realistic portrait for a client’s commission. After many hours of hard work the portrait looks good enough to show to your client for approval. Your client however, thinks the flesh tones are too yellow and wants you to fix it. What do you do? Argue with the client? Not a good idea. Return to your studio and repaint the entire face again? Wow that’s time consuming, so also not a good idea.

An easy solution is to apply a glaze over the flesh tones that diminishes the overall yellow cast. Make a glaze mixture using the opposite color of yellow — violet — along with a large amount of a clear medium. Apply this mixture thinly to create a transparent overlayer for an easy fix. See example below.

How to make a glaze

It’s easy to make a glaze with the right tools. First find something to use for mixing. You can use any type of nonporous surface as a mixing palette to make your glaze colors. Examples of mixing palettes are: sheets of glass or plexiglas, sheets of freezer paper (not waxed paper or parchment paper) taped onto a table surface, plastic disposable plates, and palette pads. Scroll down a bit for more palette ideas.

On your palette of choice, squeeze out about a tablespoon of a clear medium (more or less depending on the size of the job at hand). I’ll be using acrylic for the rest of this article however, the ideas and techniques of glazing are similar for other painting disciplines as well. Just substitute the appropriate medium depending on your choice of paint type. Oil painters will use an oil medium, encaustic painters use wax, just as acrylic painters use an acrylic medium. For acrylic painters, any gloss acrylic medium will work to make an acrylic glaze. I like to use a slow drying acrylic like Golden’s Acrylic Glazing Medium, which makes it easier to spread the glaze mixture out evenly. Tip: Acrylic mediums appear white when wet, but eventually dry clear.

Next to the medium you placed on your palette, and giving some space in between, add a small amount of the paint color you selected to make your glaze. In yet another area on your palette start your glaze mixture by doing the following. Using a knife, scoop up some medium and unload it. Then scoop up a much smaller amount of the paint color and unload that into the medium. Use a 1:10 ratio — 1 part paint to 10 parts medium. This is not an exact science. Play around with ratios and test the result to see if it is transparent enough for your use as a glaze. The most common mistake is to add too much paint color. You will be surprised at how small amount of paint color you really need for a glaze. Mix it really well with a knife so it’s all homogenized.

To apply an acrylic glaze evenly without streaks, you need to slow down the drying time, to give more time to brush it out smoothly before it dries. Oil painters don’t need to do this step because oil is already slow drying enough to blend an even application of glaze.

For acrylic, there are several options to slow down the drying of the glaze mixture. (1) as mentioned above you can use a slow drying medium to make your mixture. If you don’t have a slow drying medium you can (2) add up to 15% retarder to the paint with a regular acrylic medium. (3) Use a slow drying acrylic paint. I like to use Golden’s slow drying line of acrylics called OPEN. With OPEN use the OPEN medium along with either regular acrylic paint colors, or the OPEN paint colors for your glaze.

Once you’ve made sure your mixture will dry slow enough for your purposes, pick up a small amount of the glaze mixture with a smooth square wash brush. Apply the glaze thinly to your surface then lightly blend it to obtain an evenly applied transparent layer of color. If getting a smooth application with a brush is difficult for you, use a soft lint free rag instead of the brush. Move the rag in circular motions until smooth.

What is the difference between a glaze and a wash?

A glaze and a wash are very different techniques yet both are used to create transparent layers of color. This may be why they are often mistaken for the same thing. Let’s clear this up!

The term “glaze” refers to a transparent layer made with a mixture using substantial amounts of a clear medium, along with small amounts of paint color, as described above. A “wash” is a transparent layer made with substantial amounts of water along with small amounts of paint color. Washes are also called stains.

For washes I almost always use modern colors instead of mineral colors. This is because modern paint colors are stronger and will still hold their color when heavily diluted with water. For glazes I use both types of colors. If the idea of mineral and modern paint colors are new to you, you can read more about them here.

Since glazes are made primarily with medium and washes with water, these both need different surfaces to get good results. A wash is like watercolor and often requires an absorbent surface, like paper, to soak up the color and allow for an even spreading of color. This is very different for a glaze, which often requires a non-absorbent surface, that is glossy or satin finish, to allow the glaze to move on the top of the surface without absorbing into it.

At any point in a painting’s process, when you feel the need to apply a transparent layer, take a moment to look at the surface absorbency. If it is matte then you will get best results with a wash, if it is glossy then use a glaze. If it is matte and you would rather use a glaze, then first apply a coat of a gloss medium onto the surface. Let it dry. Since you’ve sealed the surface it has turned it into a non-absorbent one. Now you can easily apply the glaze. The reverse is true too. If your surface is glossy and you want to apply a wash, then use some product that gives a transparent grit. My favorite is Golden’s Pastel Ground, diluted at least 1:1 with water. If you don’t dilute it, it will be opaque, very gray, and may slightly veil or obscure the paint layers underneath.

Key Glazing Tips

Use enough medium. The amount of medium you use in your glaze mixtures makes a big difference. Large amounts are required to make it transparent.

Use the right order when making mixtures. Always START with the medium on your palette, then add very small amounts of paint into it. If you do the reverse – starting with the paint color, and then adding medium into the paint – the mixture may remain stubbornly opaque causing you to go through large quantities of medium to get it transparent enough to your liking.

Fixing a glaze that is too opaque. If your painting becomes too opaque in feel because you covered the underlying layers too heavily, you can sand off some of the upper paint layers once they are dry. Work by hand with pieces of waterproof sandpaper (I like grit 220) and lots of water. For large areas or heavy layers use an electric sander.

Best color intensity is achieved by using a gloss medium instead of a matte for your glaze mixtures. If you use any medium that is satin, semi-gloss or matte, then the product will contain a matting agent — a white powder that creates the matte sheen. This will definitely change the color of your glaze.

Don’t overbrush a glaze. If you continue brushing over the glaze area while it starts to dry and is tacky, it will create a “dirty” appearance. The glaze won’t appear smooth, but will gunk up and look badly applied.

Be frugal adding water. Adding too much water to your glaze mixture, over 15%, can create a hybrid wash-glaze. I rarely add water to my glaze mixtures. Washes use water as I mentioned before, while glazes rely more on mediums. Water can decrease the gloss of the glaze and therefore decrease the color intensity.

Use lint free rags. If you use a rag to apply your glaze, and it is not lint-free, then small particles of the rag may get onto your surface causing a cloudy effect. 

Ideas for mixing palettes

• A sheet of glass
• A palette pad (pads you can purchase from art supply stores or online, are made of gray or white sheets of coated paper)
• disposable plastic plates (you can keep and reuse once the paint has dried)
• sheets of freezer paper (not wax paper or parchment paper) taped to a table or piece of wood
• shellac coated wood available in art stores as traditional painting palettes

A Step-by-step Glazing example

For this example I will use the painting pictured here, applying glazes on the areas of the painting closest to the edges, to create a vignette feeling.

Dip a brush or rag (pictured here) into the medium first, picking up about ¼ teaspoon of the medium, then dip the same rag with the medium into a small amount of one or more of the paint colors. Both medium and paint will be on your rag or brush simultaneously but not mixed together. Now you can see why I call it a dirty mix glaze.

Additional Resources

Glazing on Gold Leaf

Glazing with Acrylics, Oils & Watercolors