Chiaroscuro is an italian term that means “light and dark”. It usually refers to the ability of simulate volumes using light and dark gradation of tones. The three characteristics of a color are: hue, saturation and tone. In this article I will focus on the last one. A chiaroscuro can be drawn using different medium: pencils, pens, paint and others. Using paint a chiaroscuro can be done using whatever color plus white. In this case the final picture is said monochromatic.
Renaissance painters used to paint a picture using the chiaroscuro of a color very close to raw sienna plus black. They let the monochrome painting dry for a few days or weeks and then proceeded with the colors. In this photo you can see the chiaroscuro for a preliminary version of the Virgin of the Rocks by Leonardo.
Making the chiaroscuro of an object it is possible distinguish two different cases:
- chiaroscuro of non-transparent objects;
- chiaroscuro of transparent objects.
A good chiaroscuro gives to paintings a more realistic and three-dimensional look. Usually, painters define a set of tonal values that will be used to fill light and dark areas.
Chiaroscuro of non-transparent objects
A non-transparent object when illuminated by single light source has five tonal values:
- reflected light;
- cast shadow.
Highlight is the lightest area, closely followed by light, reflected light, shadow and cast shadow which is the darkest area of the object.
A simple exercise you can do is to use only black and prepare 5 tones of gray. Try to paint a sphere as above. Put each tone next the others without blend them. When you covered all the areas blend colors. With oil and acrylic paint you have to proceed from dark to light, vice versa with watercolors.
Chiaroscuro of a transparent object
The process is similar. The only difference is that a transparent object reveals the tone of the background. In it are then visible only two tones: highlight and reflected light.