Bill Martin's Guide to Oil Painting
Shadows Create the Light
Shadows are divided into three categories. First is the shadow side of an object known simply as a SHADOW. Then the CAST SHADOW which is the absence of light caused by an object in its environment. Third is the PROXIMITY SHADOW that is caused when objects touch or nearly touch.
The SHADOW side of an object is a darker less intense version of its middle value color. (See Matching Colors) Direct light makes dark shadows. Diffused light makes indistinct shadows.
Reflected Light Within a Shadow
The light bouncing back from an object's environment is called REFLECTED LIGHT. The COLOR of an object's surroundings is evident its reflected light. See the green reflected light in the ball on the left. See the red reflecting in the middle ball. The color of the environment is a part of all shadows.
The VALUE of an object's environment is also apparent in its reflected light. The first ball is free hanging. The second ball is reflecting a white surface. The third ball reflects a black surface. The value of an object's environment is also part of its shadow.
Cast shadows distinguish themselves from other darks by always being darkest and most sharply focused near their source. Cast shadows are darker less intense versions of the color they fall upon.
Colors in a Cast Shadow
The color of a cast shadow will always contain the complement of the color of the light source, as well as the complement of the color the shadow falls upon. See the blue in the cast shadow in orange light, the orange cast shadow in the blue light, the green cast shadow in the red light and the red-violet cast shadow in the yellow-green light.
Cast Shadows Imply Form and Texture
Cast shadows describe the environment of an object. On the left the wall is defined by the cast shadow. On the right the cast shadow defines the hill.
The edges of the cast shadows define the textures of the surfaces they fall upon. Grass on the left and dirt and gravel on the right.
Cast Shadows in Direct and Diffused Light
DIRECT LIGHT (on the left) is usually from a single light source like the sun or a strong spot light. It is defined by high contrast and dark cast shadows.
DIFFUSED LIGHT (on the right) is usually from multiple light sources. It is defined by low contrast and indistinct cast shadows.
OBJECTS WITHIN A CAST SHADOW ARE ALWAYS IN DIFFUSED LIGHT where they appear flatter and less textured.
These are the dark shadows we see where objects touch each other. The dark line around a closed door, the dark line beneath the coffee mug and the dark line between your closed fingers are all PROXIMITY SHADOWS. They are relatively unaffected by the direction of the light. These shadows within shadows are often the darkest darks of a painting.
The proximity shadow at the bottom of the cylinder on the left tells us that the objects are separated. The cylinder on the right is connected to its base.