What are stretcher bar frames?
A stretcher bar is a support frame used by artists to mount canvas material on for their canvases. They are so named because canvas is usually stretched across the frame and then fastened on the bars with staples, tacks, metal spline or some other fastener. Stretcher frames are typically rectangle shapes, however, many artists enjoy painting on square, oval and even round stretched canvases.
What is their construction?
Most stretcher frames are constructed of soft, light colored wood, metal or a combination of the two. They can be purchased pre-manufactured from art supply retailers or many artists prefer to construct the canvas supports themselves. Stretcher bars come in a variety of weights and sizes to suit the specifications of different types of canvases. These include:
- Lightweight — (5/8″) — ideal for smaller paintings
- Standard (3/4″–7/8″) — most widely used stretcher bar and best if the artwork is going to be framed
- Gallery (1-1/2″) — thicker stretcher that makes it more difficult for framing
- Museum (2″ and thicker) — usually hung on the wall unframed
Most stretcher bar frames are attached together at the corner on an angle. This is called a miter. A mitered corner is the most common type for modern day paintings of the 1900s or later. Small wooden shims, called keys, are then used in the corners to help keep the canvas stretched tight on the bars and to prevent the bars from warping.