Linear perspective is a rendering technique used by fine artists to create the illusion of depth on a flat surface. It is the most basic form of perspective in which parallel lines appear to converge in the distance at a vanishing point on the horizon line. (See illustration right.) The technique is based on how the human eye perceives the world around us. Meaning objects which are closer to the viewer appear larger, while more distant objects appear to be getting smaller as they move away. Linear perspective comes into play when orthogonal (parallel) lines that recede into the distance appear to get closer together as they converge at a vanishing point on the composition’s horizon line.
There are three basic elements that must be present in a work of art in order to make linear perspective possible. These are a horizon line, a vanishing point, and convergence lines. If any one of these elements is missing, the illusion of depth is weak.
Horizon line — The horizon line defines the farthest distance of the background and is the place where a central vanishing point is established. It is the level plane where the earth’s surface (or sea) and the sky appear to meet. The line at the top of mountains or buildings is not the horizon line; these objects “rest” on the horizon line.
The horizon line will ALWAYS be at eye level regardless of whether you are at ground level or standing on a mountain top. It changes as you change position. Sometimes hills, trees and buildings or other objects can hide it from view, but the horizon line will always be present.
Convergence lines — Also called orthogonal lines, convergence lines are when sets of parallel lines appear to get closer together as they recede into the distance and meet at a single vanishing point. All parallel lines will eventually converge at a vanishing point. Sometimes they can even represent the edges of objects and some objects can have more than one set of parallels lines. An example of this would be a box or cube. Depending on where it is viewed from, we can see one, two, or three sets of orthogonal lines.
Vanishing point — The point on the horizon line where all parallel lines appear to recede and converge at is called the vanishing point. It is helpful to note more than one vanishing point can be present. This is called two-point and three-point perspective. When there are two sets of parallel lines that appear to converge, there will be two vanishing points. If there are three sets of parallel lines, then there will be three vanishing points. See The Rules of Perspective for more information.
Create a rendering by drawing a straight highway or railroad tracks using a horizon line, vanishing point, and convergence lines.
Use linear perspective to create depth in an illustration using a row of trees, a fence line, and/or telephone poles running alongside a road.
Depth is a basic building block* of all visual art. It is an important element in any composition as it creates a strong sense of reality in a painting. It can be defined as the illusion of distance or three-dimension on a two-dimensional or flat surface. A lack of depth in a composition means it will be less than lifelike.
Primary techniques an artist can use to create depth in a painting are layering and overlapping, changing size and placement, linear perspective, and relative color, hue and value.
Layering and overlapping is placing one or more elements in front of another element in order to create the illusion of depth in composition. Objects that appear in front of others seem nearer while those that are behind seem further away. This method is the strongest way of creating depth and it will over ride all other signs when there is seeming conflict.
Changing size and placement is another method artists use to create the sense of depth in a painting. This technique simply states that larger objects appear closer and smaller objects appear further away. Also objects that are positioned at the bottom of the painting appear to be in front and those at the top appear to be in the back.
Linear perspective allows artists to give the impression of depth by the property of parallel lines converging in the distance at infinity. An example of this would be standing on a straight road, looking down the road, and noticing the road narrows as it goes off in the distance. The point of infinity is what is called a vanishing point. These lines don’t actually need to be visible, though they can be. They can also be implied by the objects in the composition.
For more information about using perspective to add dimension to your paintings, read the article titled The Rules of Perspective.
Relative color, hue and value can also add the illusion of depth.
Darker colors look closer to the viewer and lighter colors look further away.
Colors that are close in value seem close to each other and strongly contrasting colors appear to separate.
Warm, bright colors (red orange, yellow) seem to advance towards to the foreground and cool, dark colors (blue and bluish green and purple) seem to recede into the background.
Saturated colors seem to advance and low saturated colors seem to recede.
Lighting and Shading
Light adds depth by casting external shadows, it also shows depth in how it acts over the surface of one object. The closer to the light source, the brighter the surface is with more reflected light.
Cast and drop shadows are another common way to add depth. Reflections work similarly in that a reflection appears on a different surface. The illusion of depth can be increased by making the shadow larger and lighter and placing it further away from the object. Blurring the edges of shadows also increases the illusion of depth.
Focus, Texture, and Detail
Objects that more detailed, sharper in focus and more textured appear closer than those with less detail, blurred or little or no texture are perceived as far away.
Space in art refers to the distance or area between, around, above, below, or within shapes and forms found within a composition. In this discussion we will be taking a closer look at several different ways space is used in art. These are:
Positive and Negative Space
There are two types of space in art: positive and negative. Both positive and negative space are important factors to be considered in every good composition. They occur in both two-dimension and three-dimension art and are complementary to one another. One impacts on and affects the reading of the other.
Positive space is the “occupied” areas in a work of art that is filled with something such as lines, colors and shapes. It is the primary subject matter of a painting; the animals, plants, building, mountain, vase, people, etc., that forms your area-of-interest. It dominates the eye and is the focal point in a composition.
In the example here, positive space (the area in black) is represented as the forms themselves… i.e. the vase, the individual letters, or the words “positive space”. It is the opposite of negative space.
Negative space is the unoccupied areas that surround the subject matter. It is more passive in nature and is defined by the edges of the positive space it surrounds. It is what gives definition to our composition.
In the example, it is the “empty space” (the area in black) or unoccupied areas that lies between objects, shapes and forms within a composition, and is also the space in the background that is not at first noticeable. It goes in all directions and goes on forever. It flows in, around and between shapes and objects.
Do you see the shapes in negative space? These shapes have substance or mass and is not simply the absence of something. This is important to remember. Negative space has weight and mass, and plays an important role in defining your subject.
Negative space is most evident when the space around a subject matter, and not the form itself, forms an interesting or artistically relevant shape. In this case the use of negative space is very much a key element of the artistic composition. In the example above, the negative space forms a shape of two men face to face.
Negative space is important in a composition because it gives balance to positive space by giving the eye a place to rest. This is a basic element that is often overlooked as a principle of a good design.
Two and Three-dimensional Space
Two-dimensional space is found on a flat surface such as a canvas. It has no depth, only length and width. In our example, the image appears flat because all the objects and forms lie on the same plane. There is no feeling of depth. However, the same space can be used to make a two-dimensional artwork appear three-dimensional by giving a feeling of depth. Three-dimensional space has width, height and depth.
When we look at a flat surface and have the sensation of looking at spaces and objects that appear to have depth, then we are receiving and believing a group of visual signals working to create the illusion of three-dimensional shapes and spaces within the painting.
These three-dimensional signals are so common in nature that we are almost unaware of them. Yet in the hands of a skilled artist these 3D cues can be used to create the illusion of three-dimension on a flat canvas surface. This occurs when a sensation of space which seems to have height, width and depth are visually created as it has been done with the vase in the example shown on the right.
The tools needed for creating the illusion of three-dimensional space are:
Changing size and placement of related objects
Relative hue and value
Overlapping objects within your composition is the simplest tool you can use for creating three-dimensional space in your painting or drawing. The effect is achieved by allowing the contour of one form to be interrupted by the contour of another form, so that it looks like one form is physically sitting in front of the other.
Another simple tool for creating the illusion of 3D space is by changing size and placement of related objects. When two shapes are the same size and are placed on the same plane, the image tends to appear rather flat and not have much depth to it. However by simply varying the size and placement of the shapes a greater sensation of depth is created.
As a rule of thumb, larger objects tend to appear closer to the viewer and smaller ones tend to recede into the background. Also objects placed lower on the canvas appear closer in distance than those which are placed higher up.
Linear perspective (a.k.a. converging lines) is a graphical system used by artists to create the illusion of depth and volume on a flat surface. As objects move away from the viewer they appear to grow smaller and converge toward a vanishing point at the horizon line. The effective use of linear perspective creates this illusion of diminishing size by treating the edges as converging parallel lines. The vanishing point may be in any direction the viewer looks, including up, and may be visible (on the canvas) or imaginary (somewhere off the canvas).
Using hue and value to create 3D space on a flat canvas surface are very important cues that tell us whether an object is near by or far away. In general, warm colors or hues tend appear closer, whereas cool hues tend to recede away from the viewer. On the same token, close objects tend to exhibit brighter, richer hues, and/or more contrasting in values, including extremes of dark and light. However, distant objects tend to be either similar or neutral in value, and exhibit grayer hues. Colors that are close in value are perceived as being on or near the same plane, but colors that have strong contrast in value appear on separate planes.
Atmospheric perspectivecombines several tools already described above. This important tool operates when objects that are far away lack contrast, detail, and texture. As objects get farther away, atmospheric perspective shows color gradually fading to a bluish gray and details blurring, imitating the way distant objects appear to the human eye.
As a rule of thumb when using this tool, remember that colors tend to pale and fade as they recede into the distance. Objects become less defined and lack detail.
When used effectively all of these tools to create the illusion of three-dimensional space will create a sense of what is referred to as deep space within your painting. In deep space there are three terms used to describe depth:
Foreground is the area of a painting that visually appears closest to the viewer. It is often located on a lower plane or bottom of the canvas.
Middle ground is space that makes up the distance between the foreground and background of a painting. There is no specific measurement for what the limits are. Typically it is located somewhere on the middle plane of the canvas.
Background is the area of a painting that visually appears to be far away in the distance at or near the horizon. It is usually located on a higher plane of the canvas.
Since a flat surface such as a canvas contains only two-dimensional space, an artist may wish to create the illusion of three-dimension. When an artist begins to cut, divide and rearrange the surface space of a flat surface, the illusion of depth may appear. Even the slightest manipulation of line, value or color will generate the illusion of three-dimensional space.
There are a number of ways to create the illusion of distance or depth on a flat surface. Here are some of those ways:
Objects that are further away, will appear smaller than those close by. Those same objects will also grow less distinct the further away they are. Their colors will fade and blend into the background colors.
Objects which are placed higher on a plane create the feeling of depth or distance. The viewer senses that he or she is standing away from the objects and that there is a large amount of space in the foreground.
Overlapping shapes tend to create a feeling of depth.
Arrangement of lights. When light is contrasted against dark, a sense of depth is felt.
Converging lines. Parallel lines, as they move away into the distance, appear to come closer together to form a vanishing point which may or may not be seen. A good example of this is a road or a path.
Colors. Warm and bright colors appear closer, whereas cool or dull colors tend to recede into the distance.
The flat back shadows and background in the painting on the left provides a good example of the effective use of positive and negative space in this two dimensional painting.
The painting on the right demonstrates positive and negative space in a three dimensional painting. Can you see the positive and negative here? The fish occupies the positive space and the water represents the negative space around the fish.
Overlapping objects is a helpful tool for creating an illusion of 3D. Depending on how it is applied can give a sense of deep or shallow space within a composition.
The Statue of Liberty in the painting on the left overlapping the river and the horizon helps to create a greater sense of depth than the painting that is on the right. On the left we get the sensation of deep space. On the right the space a shallow.
Changing Size and Placement
Changing the size and placement of the objects in these two paintings helps give more depth to the painting. Changing the size of the Indians makes them appear far away in the painting on the left. On the right, the ballerinas are on a higher plane than the ones in the front pushes them farther away into the background.
Can you see how perspective has given the three paintings above a sense of depth?
Both of these paintings have very strong one-point perspective which helps create the illusion of three dimension.
Perspective gives you the sensation that the train is moving away from you and yet it pulls you down the hallway with it in the painting on the right.
Perspective can also make objects appear 3D. The artist of this building used two point perspective to create an object that appears to have volume. Without two point perspective this building would lack depth and appear flat.
Hue and Value
Warm colors pull you up close. Cool colors recede off into the distance. The painting on the left is a good example of this tool in use.
On the right, light moves toward you and darkness moves off into the background.
As objects move off into the distance they become less detailed and more gray. For example notice the horizon and the mountain in these two paintings.