Principles and Elements of Design. http://www.candcsigns.com/blog/elements-and-principles-design. http://www.paper-leaf.com/blog/2011/02/elements-of-design-quick-reference-sheet/. Line.
The path of a moving point at the edge of a flat shape or outline of a solid object is a line. It is a mark that spans a distance between two points. Lines are most often used to define shape in two-dimensional work. They can also define contours and outlines and sometimes also suggest mass and volume. A line is longer than it is wider. The ratio between a line's width and length is called its measure.
Types of lines
Outlines– Lines made by the edge of an object or its silhouette.
Contour Lines – Lines that describe the shape of an object and the interior detail.
Gesture Lines – Lines that are energetic and catches the movement and gestures of an active figure.
Sketch Lines – Lines that captures the appearance of an object or impression in place.
Calligraphic Lines – Greek word meaning “beautiful writing”. Precise, elegant handwriting or lettering done by hand. Also, artwork that has flowing lines like elegant handwriting.
Implied Lines – Lines that are not actually drawn but created by a group of objects seen from a distance. The direction an object is pointing to or the direction a person is looking at. Implied line is the path that the viewer's eye takes as it follows shapes, colors, and form along a path, but it may not be continuous or physically connected.
Different lines have different meanings and uses. Horizontal lines imply tranquility and rest, whereas vertical lines imply power and strength. Oblique lines imply movement, action and change. Curved lines or S shaped lines imply quiet, calm and sensual feelings. Lines that converge imply depth, scale and distance - a fence or roadway converges into the distance provides the illusion that a flat two-dimensional image has three-dimensional depth. A line is an effective element of design because it can lead the viewer's eye.
Value is the range of lightness and darkness within a picture. These range from white to black with numerous shades of gray in between. Value is directly related to contrast. It is created by a light source that shines on an object creating highlights and shadows. It also illuminates the local or actual color of the subject. Value has the ability to create depth by making objects look three-dimensional or highlighting lighter, foreground aspects and receding as it hits the background.
Space, in two-dimensional design, is essentially flat; it has height and width, but no depth. There are certain visual cues, however, that can create the illusion of space in the mind of the viewer. By using those cues, artists and designers can create images that are interpreted as three-dimensional.
Size is one of the easiest ways to create the illusion of space. A larger image will appear closer than a smaller one because we observed (very early in life) that objects appear to become smaller as they get farther away.
Overlapping is another easy way to suggest depth in an image. The viewer perceives the one that is covering parts of the other to be in front and the one that is covered to be in the back.
Compositional location refers to where a form is positioned vertically in the image. The bottom is seen as the foreground; the higher an object is placed in the image, the farther back it is perceived to be.
Atmospheric perspective uses value, contrast and color to give the illusion of space. Atmospheric perspective is based on the fact that the farther something is away from us, the more the atmospheric haze may obscure our view of it. Increasing the bluish cast of an image also creates a sense of depth because cool colors recede and warm colors come forward.
Linear perspective is based on the visual phenomenon that as parallel lines (such as railroad tracks) recede into space, they appear to converge at a distant point, creating depth; it also creates a strong focal point at the place where the lines converge.
Tactile texture is the actual three-dimension feel of a surface that can be touched. Painter can use impasto to build peaks and create texture.
Visual textureis the illusion of the surfaces peaks and valleys, like the tree pictured. Any texture shown in a photo is a visual texture, meaning the paper is smooth no matter how rough the image perceives it to be.