What is the difference between a "Wash" and a "Glaze"?
What is the difference between a “wash” and a “glaze?”
I was asked this question recently at a workshop. Watercolor painters do ‘washes’;oil and acrylic painters do ‘glazing’ to achieve a similar effect. Still, many artists do washes with their oils and acrylics by diluting them with either solvents (oils) or water (acrylics). I have noticed this is especially true of watercolor painters. They also have a habit of working with a wet brush, this also has the effect of over-diluting the paint. These oil and acrylic washes may look all right but from a permanence point of view they are not a good idea. Here is the difference…
Oils and acrylics are what are called “body” paints, they are thick and viscous and the pigment particles are surrounded by the oil or resin (binder). This protects the pigment and insures that the colors remain vibrant and transparent. The binder also keeps the paint film strong and flexible. If you dilute the paint with too much thinner you wash away much of the binder and the pigment is left exposed and unprotected. This is the main reason why watercolor paintings need to be framed behind glass. You could not varnish or clean a watercolor painting without disturbing the unprotected color.
When oils and acrylics are used for watercolor-like washes the paint film and colors will look matte or dull because there is less of the binder to reflect light. Remember too that the ratio of binder to pigment is much higher in watercolor paints so the colors are more intense when diluted for washes. A wash done with oils or acrylics will also be more absorbent than normal so it will soak up binder from any layer of paint put over it leaving that new layer dull and matte as well. These ‘lean’ layers of paint will be brittle and will easily crack, especially with oil paints on canvas. If you were to varnish a thin wash of acrylic or oil paints the varnish would be absorbed into the paint layer rather than sitting on top of it where it could be easily cleaned or removed. For permanent results, any oil or acrylic paints used in this way should also be framed behind glass, like a watercolor painting.
Glazing is a good alternative when using body paints. A glaze is like a wash because the color is diluted, but not the binder! Instead, the binder is replaced by a transparent glaze medium. The glazing medium when mixed with the paint ensures that the colors remain transparent, giving life to the underpainting, while still protecting the pigment and the integrity of the film. For oils and acrylics you should only use enough solvent or water to thin the paint enough to help it spread a little easier, up to a maximum of 25%. A glaze is made by adding a medium to the color and a small amount of solvent or water when needed.
