In art, space refers to either the illusion of depth created by the artist or the artist's use of the area defined by the picture plane. The area occupied by the subject of a drawing or painting is called "positive space" while the area around the subject is "negative space." The relationship between the two affects the impact of the work. For example, a work depicting a man in otherwise empty space might suggest feelings of isolation and loneliness.
Lines are the paths created by points moving through space. Lines define shapes, lead the eye, and convey information. Horizontal lines help artists create a sense of space and suggest rest. Vertical lines create the illusion of height and often suggest spirituality. When used together, they help create a sense of stability, permanence and reliability. Diagonal lines imply movement, draw the viewer into the composition and create an illusion of depth. Sharp curves and twisted lines portray violence, chaos and confusion while soft curves remind the viewer of the human body and convey softness and sensual beauty.
Shapes and forms define the space an object takes up. Shapes consist of height and width, and are referred to as two-dimensional. Forms consist of height, width and depth, and are called three-dimensional. Shapes and forms are categorized as organic or geometric. The geometric shapes and forms include circles, squares, spheres and cones. They are generally considered man-made but they also include natural objects such as crystals. Organic shapes and forms are asymmetrical or irregular. Although generally thought of as natural objects such as plants or rocks, man-made objects can also have organic shapes. Artists working in two dimensions create art by combining different shapes. However, they can can create the illusion of form with their use of value.
Value describes the relative lightness and darkness of a composition. In black-and-white art, value includes black, white and all the shades of gray in between. Contrasting values create the illusion of space between objects, while gradation of values helps create the illusion of form. For example, lighter values seem closer to the viewer while darker values seem further away. An artist can transform a circle into a sphere with value changes that gently transition from dark to light. Many abrupt value changes help create the illusion of texture.
Texture is the way an object feels such as hard, smooth, soft or sharp. Artists create the illusion of texture in their work with line, value and even patterns. This illusion draws on our memories of how certain objects feel. For example, if an artist depicts a crumpled piece, we "know" how it feels based on our past experiences.