In a pen and wash painting, the attributes of watercolors are like personality traits of a person, what makes a person, or paint, different and unique. Each artist creates a style of their own knowing their watercolors. Understanding three attributes of your watercolors will make selecting and mixing easier–and fun.
Luminosity refers to how much light penetrate a color. A transparent color has a high luminosity. How does it work? Rays of light passes through the watercolor onto the paper and reflects back to the viewer’s eyes through the transparent paint. The more layers of wash you put, the darker the color, and the less light is reflected back.
One of the qualities of transparent watercolors is the layering of washes, of the same color or different colors, to produce a desired shade or a different color; layering means to apply one coat of paint on top of another coat of paint. There are no true transparent watercolors, but any watercolor can be made more transparent by diluting it with water.
An opaque color is the opposite of transparent color and has a low luminosity. The rays of light reflect back to the viewer’s eyes from the surface of the paint itself, some or all, and not so much the paper. Just like transparent colors, there are no true opaque watercolors, with the exception of gouache, also known as bodycolor. Watercolors that are opaque in nature can be diluted at the expense of color intensity.
Lightfastness refers to how sensitive a color is to light.
Some watercolors are permanent, meaning they do not readily fade when exposed to light over time. No paint is 100% permanent so don’t have your pen and wash in any direct sunlight for too long. Some colors are fugitive, meaning the opposite of permanent. They will fade easily when exposed to light over time.
Protect your artwork from sunlight if they are to keep their intensity of color. Framing your paintings under UV glass is one solution. Be careful if you have your art work near big spacious windows. Be sure you know where the sunlight cast its rays, from sunrise to sunset, to keep it out of direct sunlight. Some people don’t realize this until it’s too late.
Staining refers to how some paint take to the paper.
Some watercolors are high staining, which stains the paper quickly and permanently. These colors are impossible to remove no matter how much you wet and blotch them, especially after the color or colors have dried.
Some watercolors are low-staining and non-staining and can be removed from the paper leaving little or no stain; just wet the area again and blotch it with a wet brush or paper towel. This approach can also work after the paint dries.
Paint manufacturers have a rating scale of lightfastness and other attributes on watercolors and can be found on their labels and packaging. If you can’t find it, call the manufacturer for information. You should use paints that have a lightfastness rating of I or II by the testing standards of the American Society of Testing and Materials, also known as ASTM International.
Whether you use the ASTM standards, or old-fashion trial and error, selecting a set of colors that truly works for you is the number one way of enjoying your next pen and wash painting. Enjoy.