Glaze Medium - What Is It?

I see this question quite a bit on the IK WARMACHINE forum, along with "I bought some Glaze Medium, now what?" Today I thought I would try to shed some light on this subject.

The Term Glaze

I'll start by defining what a glaze is in painting terms. Simply put, a glaze is a thin (mostly) transparent layer of paint. I have it defined in our Glossary as: A transparent coating applied over a painted surface to modify the color tones underneath. That sounds a bit more complicated than it really is.

When a transparent color is applied over another, the top color alters the first. This is because light rays mix, creating a visual color mixture. You can achieve greater depth in your painting by using several layers of transparent color. In glaze paint layers, light rays penetrate the layers, strike the opaque model surface and reflect back to the eye creating various visual color mixes. The more layers of pigment that the light travels through, the greater the "depth" of color the eye perceives. Confused yet?

I could go into a long dissertation on light theory and the visual spectrum, but I'll skip that and go to a simpler example. Almost everyone has seen "3D" glasses with one red film lens and the other blue film lens. If you look at a yellow object with the blue lens, it will appear green. The same yellow object will appear orange through the red lens. Glazes work the same way. They help to filter the light reflected from an object into a different color spectrum. Take a look at the following diagram:

Using the red lens example above, the stripe on the far left is a yellow object. The next stripe is that same yellow object with a thin red glaze over the top of it. It now has an orange hue. Each stripe after the first is another glaze layer on top. The solid red stripe on the far right is an opaque version of the color used in the glaze. Bored yet? Me too. Let's get to the good stuff.

Vallejo Glaze Medium - How Much To Use?

I'm talking specifically about Vallejo Model Color Glaze Medium, bottle #596. There are plenty of other glaze mediums on the market from other manufacturers, but this is the one I like. It not only makes glazes from a wide range of acrylic paints, it dries flat and also acts as a drying retarder. I've frequently had high mixes of glaze stay wet on my palette for days at a time. But I'm getting ahead of myself. How much to use?

I like to relate Glaze Medium to a transparency slider in Adobe Photoshop for those who have used it. Paint straight out of the bottle would be 100% or solid. Glaze Medium straight out of the bottle would be 0%, or completely transparent. The trick is finding out just how transparent you want your paint to be. Lucky for me, I had a Zealot unit jump up and volunteer to test the mixing ratios for us. I'm just painting the mixes straight over white primer for the best visual feedback. My test color is VMC 150 - German SS Camo Brown, one of my favorite colors. (I'm killing two birds with one stone here, as this color forms the base color of my units robes. ;) )

Volunteer #1

The Zealot Leader stepped up and will serve as our baseline color. No Glaze Medium was added to the paint, just a touch of distilled water to get it to flow smoothly. This is only one coat. VMC 150 has good coverage by itself, another reason to use it for this test.

Volunteer #2

Zealot #2 receives a mix of 1:1 VMC 150 : Glaze Medium (GM). Just a bit weaker than straight paint, but it flows nicely.

Volunteer #3

Zealot #3 receives a mix of 1:2 VMC 150 : GM. Already it's showing results. The white primer is starting to peek through on the high points, but it's remaining opaque down in the crevices.

Volunteer #4

Zealot #4 receives a mix of 1:4 VMC 150 : GM. It looks like the model is starting to shade itself.

Volunteer #5

Halfway through the squad now. Zealot #5 receives a mix of 1:6 VMC 150 : GM. It looks like it's seriously time for laundry day.

Volunteer #6

Zealot #6 receives a mix of 1:8 VMC 150 : GM. More white than brown showing now. Getting closer to a true glaze.

Volunteer #7

Zealot #7 is my first winner. He receives a mix of 1:10 VMC 150 : GM. It may not look much different than the 1:8 ratio, but experience tells me this is about where I need to be.

Volunteer #8

Zealot #8 receives a mix of 1:12 VMC 150 : GM. This is my favorite ratio for glazing. If it turns out too light, a second application in selected spots will almost always give me the results I'm after. I premix most of my glazes using this 1:12 ratio.

Volunteer #9

Zealot #9 receives a mix of 1:14 VMC 150 : GM. This is getting more subtle. It's hard to believe this started out as a dark brown paint.

Volunteer #10

The last Zealot in the squad receives a mix of 1:16 VMC 150 : GM. Other than the deep recesses, it just looks like dirty linen. This can be used to add a light layer of grime to areas you want to look less than clean.

Now you might be saying to yourself, "1 to 12, that's 13 drops of paint for one color! Holy cow!" or something similar. I have found that when I mix a glaze that I like and I plan on using it again, it's best to have some empty dropper bottles and premix it right in the bottle. That way when I need it again, I just put a drop or two on my palette. It saves a lot of medium in the long run, and I don't have big puddles of glaze all over my palette. On the front end though, I've gone through 3 full bottles premixing various colors. I went through half a bottle in the test on the Zealots.