A stretcher bar is used to construct a wooden stretcher used by

artist An artist is a person engaged in an activity related to creating art, practicing the arts, or demonstrating an art. The common usage in both everyday speech and academic discourse refers to a practitioner in the visual arts only. However, th ...

s to mount their

canvas Canvas is an extremely durable plain-woven fabric used for making sails, tents, marquees, backpacks, shelters, as a support for oil painting and for other items for which sturdiness is required, as well as in such fashion objects as handbags ...

es. They are traditionally a wooden framework support on which an artist fastens a piece of canvas. They are also used for small-scale

embroidery Embroidery is the craft of decorating fabric or other materials using a needle to apply thread or yarn. Embroidery may also incorporate other materials such as pearls, beads, quills, and sequins. In modern days, embroidery is usually seen on c ...

to provide steady tension, affixing the edges of the fabric with push-pins or a staple gun before beginning to sew, and then removing it from the stretcher when the work is complete. Stretchers are usually in the shape of a

rectangle In Euclidean plane geometry, a rectangle is a quadrilateral with four right angles. It can also be defined as: an equiangular quadrilateral, since equiangular means that all of its angles are equal (360°/4 = 90°); or a parallelogram containi ...

, although

shaped canvas Shaped canvases are paintings that depart from the normal flat, rectangular configuration. Canvases may be shaped by altering their outline, while retaining their flatness. An ancient, traditional example is the '' tondo'', a painting on a round p ...

es are also possible.

Construction

Since a stretcher is simply a frame, it can be constructed in a variety of ways. The differences in construction have to do with how the corners are built. Commercially available pre-fabricated stretchers come in segments with interlocking corners, that can be fit together like puzzle pieces. Corner supports can also be made using simple woodworking techniques, however. In the case of the French stretcher, a

mitre joint A mitre joint (often miter in American English) is a joint made by cutting each of two parts to be joined, across the main surface, usually at a 45° angle, to form a corner, usually to form a 90° angle, though it can comprise any angle greater ...

is used to adhere the corners. "Keys" or small triangle wedges are inserted in the joint after stretching the canvas to give the canvas its final tension. When fastening the canvas, pressure should be distributed evenly around the stretcher to minimize warping due to unequal distribution of pull. Unlike other types of stretchers, the corner joints in French stretchers are not glued or fastened in any permanent way. This allows the canvas to be re-tensioned later, as it has a natural tendency to stretch and sag over time. In contrast, strainer bars stretch canvas in a fixed (non-adjustable) way. A simpler form of stretcher employs

butt joint A butt joint is a technique in which two pieces of material are joined by simply placing their ends together without any special shaping. The name "butt joint" comes from the way the material is joined. The butt joint is the simplest joint to ma ...

s to adhere the corners. The joint is pinned and glued into place and can not be expanded after assembly.

Design

The profiles on the stretcher bar should be slightly rounded. This has three advantages: # It allows the framer to see and obtain clear edges on images that have precise borders # It allows the canvas weave to "roll over" the profile rather than snap over a sharp edge which is a major cause of canvas cracking. #It also increases the surface area of the frame, which reduces its friction with the canvas. This will make it easier to pull the canvas and make it more taut. There are many different stretcher bar profiles, and many different styles of cutting the wood. So it is impossible to say anything is "standard." There are also many big regional differences in the style and cutting of the wood, due to the historical reasons. For the same reasons, the wood used for making stretcher bars differs a lot from country to country depending on the forest that is present. But most stretchers, to avoid warping is made in well dried Nordic pinewood sourced from

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, and

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. Another way in which stretcher bars can be strengthened is by having a

cross brace In construction, cross bracing is a system utilized to reinforce building structures in which diagonal supports intersect. Cross bracing is usually seen with two diagonal supports placed in an X-shaped manner. Under lateral force (such as wind or ...

inserted. It is advised that lengths over 40" or 1m be fitted with a cross brace. By doing this it ensures the wood will not warp and will hang flat.

Uses

The use of stretcher bars in the home print market has become increasingly prominent with

inkjet Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range from small inexpensi ...

-printed

prints becoming more popular in the home. This has given a rebirth to this old technique used in the art market for so many years. Although artists use blank canvases and pre-stretched canvases in the art business, many photographers use stretcher bars for framing wedding photography and reproduction of photographic prints. Stretcher bars are also used in picture framing when framers are framing things like sport shirts etc. Stretcher bars are used extensively in theatrical productions for framing material backdrops. When a photographer takes a picture then digitally transfers this onto a canvas via inkjet printing, he then stretches this over a stretcher frame. By wrapping the canvas all the way around the frame, known as gallery wrap, the photographer can then hang his picture on the wall, already framed.

References

{{Reflist Picture framing Painting materials

Construction

Design

Uses

See also

Further reading

References