Even though I’ve written several articles on glazing I came to realize that “glazing” is often misunderstood and could use some defining. So, what is a glaze? The most common answer is that a glaze is transparent. Well, that may be true, but that is only one part of the answer. My definition of a glaze is a bit fuller: “a subtle transparent evenly applied layer of color”. Let’s look at why I define it this way.
The new modern pigment colors (ie Quinacridones, Phthalos, Dioxazine) are often called transparent, so can these be used as glazes? Not by themselves, and here is why. When they are applied thickly they are opaque. When they are applied thinly they are transparent but are so incredibly vibrant that they will overpower anything they overlay.
Let’s take a moment and ask why we care about glazes anyway. When would using a glaze be an appropriate technique? Let’s say you were painting a portrait commission in a realistic style, and after months of hard work the portrait was as perfect as you can get it. Continuing this imaginary scenario you then proudly show the portrait to your client who feels the skin tone is overall too yellow. So what do you do? Argue with the client? Not a good idea. Take the painting back to your studio, remix all the colors and repaint the entire face again? Also not a good idea. There is an easier solution. Applying a transparent layer of a purple color (purple is the opposite or complement of yellow on the color wheel) to neutralize the yellow coloring.
So now lets get back to our discussion of the modern colors. By wrongly assuming that any modern color is transparent and therefore by itself would make a good glaze, we could grab our tube of Dioxazine Purple and apply it thinly (so it’s transparent) over the entire portrait face. Now to our horror we see that this purple color, even though it is transparent is so intense it has turned the face to a vivid purple. We could try to convince our client that this modern style might be a better approach to their portrait, or we could take another look at my definition of a glaze again. Being transparent isn’t enough for a glaze to be of help in a situation like this. Remember the full definition of a glaze is “a subtle transparent evenly applied layer of color”. So still using the Dioxazine Purple we have the transparency, but how do we get the “subtle evenly applied” qualities?
Start a mixture on the palette using a clear polymer medium (if you are working with acrylic) and add a very small amount of the Dioxazine Purple (about 1 part paint to 10 parts medium), mix it really well with a knife so it’s all homogenized, making the color more subtle. To apply it evenly, however, we need to slow down the drying time. Adding up to 15% retarder to this mixture will slow down the drying. Another alternative is to use Acrylic Glazing Liquid (contains 15% retarder to 85% polymer medium gloss) for your medium. Now with a smooth flat brush, apply this mixture (1 part Dioxazine Purple to 10 parts slow drying medium) in a very thin application to obtain an evenly applied transparent layer of color. And voila (!) our overly yellow portrait is now neutralized to a more acceptable flesh tone. Use glazing for shifting colors as well as many other uses.
Even though my directions are for use with acrylic paints, the same applies with oil. Just substitute an oil medium instead of the acrylic mediums I mentioned.