Paint has physical characteristics which can be exploited for the creation of interesting surfaces. In fact, If you did a painting in nothing but titanium white, but manipulated the surface, there would still be an image created by the shadows. The use of heavy opaque paint can rise to meet your viewer or one can also create a physical depth to the paint that is useful in conducting light and giving a painting the glow that many early Dutch paintings have. These manipulations are called glazing (the use of transparent layers of paint) and impasto (which means heavy paint, but the surface can be modeled as well).

Glazes

Using Oil and Acrylic Glazes: When using glazes in a painting it is first and most important to limit one's palette to only transparent or semi transparent colors. These colors must then be suspended in a glazing medium (a transparent binder) and be applied in multiple layers.

• OIL PAINT: A glaze painting is a painting that takes full advantage of the transparency of oil paint. This is achieved by layering transparent washes one over another. Avoid cadmiums and titanium white (except as finishing highlights) because these are opaque pigments. Phthalocyanines, Alizarin Crimson, Hansa Yellow, and Zinc White (use Zinc White sparingly because it is semi-opaque) are best. Mix liberally with medium (1/3 Damar, 1/3 Turpentine*, 1/3 Drying Oil). Surfaces should be flat. Allow the white ground to show through to help control the lightness of each color as it is applied. One week drying time between each layer is recommended. Finish with opaque highlights. Wax medium, which is a wax-based medium for use with some opaque pigments, can help make opaque pigments more transparent.
  * Use only turpentine with Damar because Mineral Spirits will not completely dissolve Damar.
• ACRYLIC PAINT: Acrylic glazing has just recently caught up with oils. Acrylics were formerly very flat compared with oil, but materials such as transparent soft gel has made it possible to create clean clear glazes with transparent color. Like oil, one must use only transparent color and build up layers. Although acrylic paint dries quickly, the additional gel slows drying time and one should wait several hours between layers. Finish with opaque highlights.

Impasto
and
Modeling

• IMPASTO: Impasto is merely heavy paint. The simplest way to create an impasto surface is to apply paint in large heavy quantities, usually with either a brush or palette knife. Because most oil and acrylic colors have a buttery consistency, this can be achieved by working directly from the tube. This will create an opaque surface. In the past all impasto techniques were done with only opaque color because traditional transparent oil mediums were very fluid. Now there exists a number of commercially-produced, high solid transparent oil mediums which can be used for creating physical surfaces. These materials have the ability to "hold a peak," or dry in the same shape as when applied.
• AGGREGATE: This is a material that is added drectly to the paint to create a physical texture. This may be sand, metal shavings or any other solid material that does not react with the paint. Apply like impasto.
• MODELING: This is sculpting on the surface using modeling paste or a similar material before the paint is applied. Modeling paste has a putty-like texture and should be applied with a palette knife. The surface can be softened while still wet by using a wet cloth or wet brushes. It is recommended that one only use this material with an acrylic gesso ground, because it will not adhere well to an oil ground. If an oil ground is to be used, apply directly to canvas or panel before applying painting ground.

updated 07/14/04