All you need to know about it!It is a pretty safe bet, that just about every painting you have ever seen hanging on a wall, has first been stretched around stretcher bars before it was framed. Some artists paint on already stretched canvases, and others tack their canvas up to a wall or other rigid structure & paint on it before it gets stretched. Stretching can be a tricky thing..
What exactly does stretching mean?Well, to stretch a canvas means pulling the fabric tightly around a wooden infrastructure & stapling it to the back so the finished product has an even, wrinkle free, drum-like thud to it. This allows the image to be seen clearly. To determine the size of the painting you must do one of two things. If the painting has already been completed, simply measure the exact dimensions of the painted area on the canvas and build the stretcher bars to suit. If you are not confined by an already painted piece, then build the stretcher bars to any size you want & start the stretching process from there!
The secret to a good stretchJust like most aspects of life, a well stretched canvas is all about balance. You need to work your way around the canvas pulling in the opposite direction of the last staple you just put in the frame. See diagram for the proper technique
As you can see, it is more difficult than it appears. This is especially true of a canvas that has already been painted on. The image has to remain lined up even though you are working with the painting face down.
The two styles of stretchingThere are two different ways to stretch a canvas. The first is called gallery wrapping. This is when the image is painted all the way around the sides of the painting. Typically these are stretched on deeper stretcher bars and can be hung without framing them. (See more on canvas framing here.)
The second is when the painting stops without continuing around the sides of the bars. This is the most common style of stretching and tends to need a frame because the sides are left white and usually messy. Framing the stretched canvas covers up the unfinished sides & really completes the look of the painting.