Gouache paints differ significantly from other art mediums.
The mystique of gouache paint begin with its name. (It's pronounced "gwash.") It comes from the Italian word "aguazzo," which means "mud." It is also known as bodycolor in the company of art history professionals. Gouache paint features idiosyncratic features which require an experienced hand to use effectively.
Drying and Repainting
Gouache is known for drying extremely rapidly. However, it does not dry within the fibers of the paper or surface onto which it is applied. As it dries, gouache changes color: lights grow lighter, whereas dark shades darken even more. As gouache experiences no chemical altering as it dries, it can be reworked, oftentimes for years. This feature also makes gouache susceptible to cracking and peeling. Experts recommend using gum arabic between coats to bind the paint.
Thickness of Application
A single brush stroke of gouache paint contains a great deal of paint, resulting in a unique thickness. This density creates a flat and aesthetically perfect area of color. It also allows for gouache to be used on white or tinted canvases, its color's quality unchanged. Gouache also resists the affects of water on its quality. The paint's denseness, alongside its capacity for being reworked, can tempt amateurs into applying too much paint, which can result in cracking.
Painting Style
Gouache's qualities encourage a direct style of painting. It completely covers any paint layers beneath, and is never applied by glaze or tint. To lighten gouache paint, you should not use water; rather, add white. Experienced painters refer to gouache's "live" quality and mention that stroking over one layer of paint can sometimes activate the layers beneath it, a technique known as "lifting." Architects and commercial artists frequently sing gouache's praises for these qualities.
Connections to Other Types of Paint
Like gouache, acrylic paint also dries quickly. However, acrylics don't dry as fast as gouache, nor can they be reworked after drying. The most similar type of paint to gouache is watercolor. Experts even refer to gouache as a type of opaque watercolor. You can use the same type of bold strokes with oil paints that you would with gouache, with the exception of impasto. That technique, dependent on a thick layer of paint, does not play to gouache's strengths.
