Light ... a LOT has been written about this topic, so I won't even attempt an exhaustive synthesis. But, Arnheim mentions a few things that interest me. He discusses both rendering the effect of light in a painting and the symbolism of light.
1. Rendering light - typically, artists model the volume of an object by rendering the effects of light upon it. This involves depicting highlights, body value, body shadow, cast shadow, etc. Here's an example that I painted from (what else?) an eggshell:
2. Symbolism - the source of the light can impart special meaning to a painting. That is, light that is cast upon an object may mean something entirely different from light that is emitted from the object itself. Here are two examples from Rembrandt's work:
In this painting entitled Adoration of the Shepherds, the major source of light is coming from the Christ child in the manger: a symbol of "divine light."
However, in The Prophet Jeremiah Mourning Over the Destruction, Rembrandt uses a narrow beam of light from above to illuminate part of a dark scene. Symbolically, the light from above is falling upon the dark humble human habitat, symbolizing the inferior position of man.
There are so many other symbols attached to light, that I can't begin to list them all here. Believe it or not, I was very concerned about the source of light in my eggshell series. Sometimes the light falls upon the shells from an external source, but more often than not, the light is internal. This is because the series utilizes fractured eggshells as a metaphor for the effects of pressure upon life, the human psyche, and our investments. After it has been cracked, the shell cannot be restored to its initial pristine structural state and fragmentation is the result. As psychological portraits, each painting in this series relies upon the transformation of ordinary eggshell fragments into a single complete entity that possesses a unique personality or mood. This is achieved by imposing a highly chromatic design onto the arrangement, and creating directional focus that, in some instances, adds the time dimension. Luminosity is the desired effect in most of these paintings because it implies a life-force which is the essence of the new entity that has emerged from the fragments.
Now, let's take a look at the practical matter of rendering light in a painting. Arnheim asks: How does Rembrandt obtain his glowing luminosity? Here are some of the ways:
- Value contrast (chiaroscuro). Placing high value colors within a surrounding region of darks.
- Keeping shadows to a minimum on the lit object.
- Confining the strongest light within the confines of the object emitting the light
- Putting little detail in the areas of highest brightness.
- Surrounding the pure hues of the light with dull color.
Light may also be used to convey the idea of "nothingness." Arnheim points out how objects can vanish into lightness. This is a practice commonly used by landscape painters who deal with atmospheric effects upon light. My Fibonacci spiral below is based on the same idea of objects vanishing into space, which happens to be light:
Arnheim also mentions that The impressionists played down the difference between light and shadow and blurred the contours of objects. Impressionism at its most extreme is pointillism, in which each dot is a light source of its own. Take a look at Seurat's The Eiffel Tower:
BTW - this kind of illustrates our discussion yesterday about design vs. color. Without design, these colors wouldn't have made much sense. But, color is at least as dominant as design in this painting.
OK - I've probably said enough even though there's soooooo much more! But, I'll leave it to all of you to "illuminate" us with your great comments :)