What are the methods that artists use to make a flat two dimensional surface appear three dimensional?
1. Linear perspective
The concept of linear perspective is a mechanical system that attempts to describe how we actually see the real world.
This mechanical system was developed in the fifteenth century by Filipo Brunelleschi of Florence, Italy. When drawing buildings in a street scene, he happened to extend the lines of the buildings and noticed that they converged to a point in the distance. Soon after, many more artists in Italy were drawing compositions with geometrical perspective as a major part of the drawing.
It can be a difficult subject for many artists to understand, however. If you want to study perspective in more depth, a self-published book on perspective is available on my website.
One noted artist who understood the concept very well was M.C. Escher. He created drawings that played with perspective, creating optical illusions that conflict the viewer's understanding of perspective.
One of his more noted pieces, "Waterfall",
below, creates the illusion of water flowing uphill.
An edge is where two different values or colors meet. Extreme differences create a hard edge and similar differences create a soft edge.
Hard edges tend to make objects appear closer and soft edges make objects appear to be further away.
The easiest and most obvious method is overlapping. An object placed in front of another object is closer.
The three circles are the same color and value. Overlapping them makes the color more intense as shown in the center section.
Other words used to describe this property of color are, brightness, chroma, saturation and purity.
Intense colors appear closer than colors that are not intense or grayed.
The warm red and orange colors appear to bring the objects in the foreground closer, while the cooler colors help give the illusion of objects receding in the background, giving depth to this demonstration painting.