|Nicole at Mille Fleurs 3, acrylic painting on canvas,
48 x 30, 2010.
|In the Afternoon Light, acrylic painting on canvas,
48 x 30, 2011.
Contrast is the difference between light and dark values. The human eye is able to see clearly across a contrast ratio of about 15,000 to 1 (the brightest area 15,000 times brighter than the darkest area). Paintings, by contrast, have a maximum contrast ratio said to be at most 100 to 1.
This presents a problem for painters—how to achieve the impression of natural contrasts without being able to show them directly. This problem is most urgent for painters who depict scenes lit by direct sunlight, where the brightest highlights and the darkest shadows share a composition. There is no perfect solution to this problem, but painters who invest in contrast expend a great deal of thought and effort in understanding visual cues that are interpreted unconsciously as contrast.
In Nicole at Mille Fleurs 3, most of the figure is in direct sunlight. Selbach paints a full range of values in the lit areas, and lets the cast shadows drop to black. The eye would naturally be able to see detail in the cast shadows, but by painting them black, Victoria subliminally tells the brain, "this region is too dark to see." The brain then identifies these shadows as about 15,000 times darker than the highlights, heightening the implied contrast with the lit areas, which are nowhere near 15,000 times brighter than the blacks.
In her painting In the Afternoon Light, Ms. Selbach uses her other contrast-enhancing technique. Most of the figure is in shadow. So if Selbach had followed her "shadows = black" rule, the composition wouldn't have worked. Instead, she renders a large range of values in the shadows, and lets the lights go to white. Again, she gives the brain a strong cue for a full 15,000 to 1 contrast ratio, helping to work around the contrast limits of acrylic paint.
Notice that in the first painting, the technique gives a sense of warm, rich light and burnt shadow. In the second painting, there is a sense of cool, glowing shadows and diffuse, washing fields of light.
Selbach focuses on techniques for conveying extremely high contrast, because sunlight and shadows shown in natural light are her inspirations. She has mastered the contrast techniques described here, but many others exist. The key to discovering your personal preferences is to think about how you see what you see. Feel free to share your own tips and observations in the comments.