PICTURE PLANE
Two-dimensional design takes place on a surface called the picture plane. The picture planes you have been using to make your projects on are the pages of your Design Book. For a painter it is the canvas, for a muralist the wall.

The significance of the picture plane becomes apparent when you think of the image on picture plane as being like what you would see if you were looking through a window. A flat image, like one of your figure/ground projects, appears to be pasted to the window (picture plane) with no space extending beyond it. A photograph or any image that shows the illusion of space appears to extend beyond the picture plane. In rare instances it is possible to make the image project in front of the picture plane.

FORMAT
The format is that part of the picture plane that the design take place in. If nothing is done to limit the format the entire page, canvas, wall, etc. becomes the default format.

That is one reason why a background or a border is generally a good idea for an image unless it is the right size and shape to fit comfortably on the page (how many good designs are automatically 11 inches by 14 inches?). Much two-dimensional art is reformatted to make a better composition -- unless it is carefully designed to fit the ground (like most paintings on canvas).

Simple geometric shapes generally work best for formats. Complex shapes are likely to be seen as an extension of the image leaving the entire picture plane to be the format.

OVERLAP
Overlap is where objects appear to be on top of one another each closer to the observer than the next. There is no clue, using only overlap, as to how deep the space is. All you can tell is what thing is closer to you than what. If overlap is used alone with flat shapes, like the figure/ground and balance projects, the space remains fairly flat.

When items appear round (occupy space) the illusion of depth is generated.

Shading is modeling with light and dark.

SHADING
Shading is the way to make objects appear three-dimensional on a two-dimensional surface. The different values created when light hits a three-dimensional object cause that object to be seen as occupying space.

Light usually comes from above so we read images in that way. The two discs to the left appear to be convex or concave depending on what direction you think the light comes from. For a fascinating look at how light direction affects shading check out the last example at http://server.esc.cquest.utoronto.ca/psych/psy280f/ch7/shading.html

There are five different kinds of light used to shade objects in art:

The highlight is the lightest part of a round surface. The highlight is usually inside of the edge that is lit. This gives the surface the look of curving all the way around the back.

It is called a lighted plane if it is a flat surface.

The transitional light describes the middle values between the highlight and the darkest shadow. This is a modeling shadow because it is what makes the object look round. It has soft edges on round objects.

On an angular object there are abrupt changes in value where the planes change direction.

The core of the shadow is the darkest part of the shadow -- the place where the least light hits the object. An object looks rounder when the core of the shadow is in from the edge.

Reflected light is what makes the core of the shadow appear to be away from the edge of the object. It is where light is reflect from a nearby area onto the object. Careful observation of reflected light will help you make objects more convincingly round looking.

The cast shadow is the shadow the object casts onto another surface. This kind of shadow usually has a hard edge, which can help you distinguish it from a modeling shadow. A cast shadow will be darkest closest to the object casting it.

DEEP SPACE
Overlap can give a priority to what is nearest and farthest but cannot tell how much space is involved.

Shading can make objects look three-dimensional but that limits them to occupying shallow space. It takes perspective to give the illusion of deep space.

In deep space there are three terms used to describe depth:

Foreground means in front -- the area immediately in front of the observer.

Middle ground is in the middle. There is no specific measurement for what the limits are -- it is just in the middle.

Background is in the distance. The term means behind (in back of) something. In a landscape it means far away. For the project for this lesson it means very far away.

There is a great deal of latitude as to how much space each of the above occupy. In general the foreground is in the front, the background is in back and the middle ground is in the middle.

There are situations where one of them is missing. In a controlled space, such as in a room, there may be no background (that is there may be no deep space even though the walls of the room provide a background for the objects in the room). In some instances there may be no foreground visible (only distant landscape). A foreground object in front of a distant background may eliminate the middle ground.

It is important to be able to control how much depth is in your images -- from flat to shallow to deep space. It is necessary to knowing perspective to successfully create the illusion of depth in an image.

There are two systems of perspective: linear and atmospheric.

LINEAR PERSPECTIVE
Linear perspective is the perspective most people are familiar with. It was formalized during the Renaissance and is based on the concept that an object appears smaller as it gets farther away from an observer. The "lines" in linear perspective are used to diagram how much smaller the item would appear.

The second half of this lesson will give you the basics of linear perspective.

ATMOSPHERIC PERSPECTIVE
Residents of Southern California are all too aware that air is not always clear and transparent. Atmospheric perspective is based on the understanding of how air acts as a filter to change the appearance of distance objects.

Go to the second half of this lesson to learn more about perspective.