Shapes are made up of lines joined together. Shapes are two-dimensional and depict more than just silhouettes. Shapes also represent blocks of value (shadows, mid-tones and highlights) and blocks of color.
Silhouettes are the outlines of objects, animals and people. Humans quickly and intuitively identify silhouettes before thinking about or processing other details of a picture. Elephant, giraffe, tree, flower…we may not immediately think of the details, but the overall shape of each example is clear and distinct in our mind. A picture that has a clear silhouette will have a stronger impact on the viewer. In other words, the viewer will be able to more quickly comprehend what is portrayed.
Value shapes (light and dark) play a key role in giving a three-dimensional impression of a scene or object in a picture. Value shapes can also be used to more clearly depict the form (sphere, cube or cylinder) of an object. For example, a shadow may appear as a straight line when it stretches over a cylindrical object. But the cylindrical form will be more clearly depicted by arching the shadow over the cylinder with a cross contour line. Value shapes have one other important quality, their ability to affect the mood and atmosphere of a picture by masquerading as a silhouette and exhibiting some of the features of a person. For example, a shadow that appears to be the approach of a menacing person creates a dark and frightening feeling.
A color shape is a block of color with a direct link to a specific object. Color shapes work closely with value shapes. When an artist creates clear value shapes, much of the variation that appears in a realistic setting is lost and lumped into one of the few chosen values. This is where different color shapes with the same value can bring back the detail that was lost by creating a distinct edge between the different colored objects.
Plan the shapes of a picture from the beginning, making sure they will be easy to read. A completed picture will be complicated enough without the distraction of an unclear shape.