Canvassing Canvas - What you need to know about Canvas Stretching

Round canvases are stretched around a round stretcher bar with a series of little folds and tucks

So you have been following that artist you love for awhile now, and you finally decided to take the leap and purchase a painting. When you placed your order you were pleasantly surprised at the shipping costs but when the painting arrived, it was in a tube and most definitely cannot go right on your wall. Showing this piece in your home has been something you've really been looking forward to, however it's not going to have the impact you were hoping for secured to the dining room wall with push pins. Now what?

This is a pretty typical challenge that becomes more and more common, as we do much of our shopping online, and what we don't know before it arrives adds unforeseen layers to a project.

What is canvas stretching?

Canvas stretching, simply put, is taking a flat piece of canvas, and wrapping it over wooden supports to give it structure and dimensionality. Stretcher bars, are the name we use for these wooden supports. These bars are usually made from a wood that is strong and straight and has been kiln dried to assure that the wood will not twist or swell along its grain. The size of the canvas will determine the thickness, or weight, of stretcher bars and number of cross supports that are necessary for your project. Large canvases require greater tension to support the weight of the fabric and paint, and will require larger thicker bars to hold their shape against that tension. Smaller canvases only require an outer support to give the canvas shape in the frame.

Large or historic canvases may require a process called rigid backing to offer support without putting excessive tension on the tacking edge or cracking delicate paint layers

Valuable or historic pieces will benefit from a stretcher bar with adjustable, or "keyed" corners, allowing the tension on the piece to be increased without removing the painting from the bars. Modern or decor pieces can be stretched on strainer bars, a joined stretcher bar that cannot be resized. These are individual decisions to be made with your framer, and will be unique to your project.

The canvas is then 'stretched' over the bars and is held in place with staples, on the side or back. Staples on the back of a canvas are called a gallery wrap, allowing the painted surface to wrap around the outer face of the bar and are currently considered industry standard. A standard stretch puts the staples on the sides of the canvas, and could be called a 'traditional' stretch, as that it is most often seen in older pieces where the art ends at the forward facing rim of the stretcher bar. The artists original intention and the size of the piece will dictate which of these options is best for your art.

The corners of the canvas are folded into a neat packet that lays flat at the back of the canvas, and allows for expansion, whether due to humidity, keying or other environmental changes.

Artists when selling paintings online, unless otherwise specified, tube ship their paintings for the sake of economic necessity. Shipping a large, flat object, even one that is fairly light can get expensive. As with all art and documents, we need to get them out of the tube and stored flat as soon as possible.

Art on paper, is URGENT to get out of tubes and into a flat file or folder as soon as it arrives. Canvas gives us a little grace. If packed and wrapped properly a canvas can be stored in a tube for a time, although we don't want this to be an extended period of time in which the canvas and paint may become rigid, or the ends may take on crushing or folding. Canvas stored in tubes should be wrapped around a support that is longer than the canvas is wide, preventing the canvas from resting on its fabric edge inside the tube, sandwiched between protective sheeting, with the paint facing OUTWARDS to avoid micro cracking in the paint that can result in future paint loss and should be cushioned against resting points against the outer tube. Ideally, any extended storage should be in a flat foamcore folder and protective sleeve or archival box and storage should ALWAYS be in a temperature controlled and insect/ dust free environment. No garages, no attics. If bubble wrap is used, face the bubbles AWAY from the painting to avoid the texture coming into contact with the paint.

When your painting arrives, do take it out of the tube and examine the piece for completeness, correctness, and quality. Some things to look for are whether the image is the one that you selected, the thickness and quality of the canvas are what you selected, and to note any damage the piece may have taken in the packing and shipping process.

Canvas stretching uses canvas pliers, stainless steel staples and a wood frame to give a painting structure and dimensionality.

Things to be aware of

Often artists will ship a canvas before the paint has fully cured, a process which medium and humidity dependent may take weeks or even months. On fresh oil paintings the artist will use a cling film over the art to prevent an uncured painting from sticking to itself when rolled. This film can be left in place until the canvas is ready to be stretched. It will prevent dust and other environmental contaminants from sticking to the face of the painting and becoming one with your art before the paint has dried beyond any internal moisture making the outer layers tacky or soft.

How wet is too wet? If the canvas feels limp or tender from moisture, this is a canvas we are going to want to lay out flat in a warm dry room to gently encourage the drying process. It is a natural part of the process, however, avoiding mildew or mold from excessive moisture in the canvas is very important to ensure the longevity of your art. These contaminants not only leave visible staining on a canvas, but will damage the fibers of the canvas, weakening it, making it more prone to cracking, tearing and paint loss and can shorten a paintings lifespan by years and even decades.

Next we can look for any damage that may have happened during the packing and shipping process. Has the painting been stretched and removed from its previous supports before it was shipped? Some artists will paint with the canvas attached to a stretcher bar, and others will use pre-primed, unstretched, rolled canvas for their work. We can tell which they have used by examining the tacking edge, the white space around the canvas for the staple holes where it was previously held to the stretcher bar. Depending on the canvas type, how aggressively it was tacked during previous stretches and how many previous stretches the piece has had, the tacking edge may be weakened and require reinforcement to be securely stretched for your display.

A high quality artists canvas that was correctly tacked can be removed from its previous supports and re-stretched many times before it will need restoration of the tacking edge. A craft store canvas will not hold up to many re-stretches. This is why the pre-stretched canvas that you buy at the craft store cost significantly less than a high quality artists canvas. They are made for single use, and are often called student canvases.

An unstretched canvas will have no tack holes, might be painted all the way to the edge or might not have been properly primed. Unfortunately, artists often don't have the education in structural materials, or have budget constraints that result in a canvas that will need special care to show at its best. The best way to learn more about the quality and materials used to prepare an artists paint surface is to ask!

These things are not necessarily going to result in a canvas that cannot be displayed, but they will create the need for special considerations when the canvas is stretched and framed.

Neither of these canvases are, without qualification, better than the other. A previously stretched canvas can be of poor quality or can have other damage from the previous stretch, such as wear and tear in the corner folds, or paint may have been added after the canvas was removed from the bars, creating cracking points where additional paint was applied when the canvas was not tensioned, over paint that was applied when the canvas was tensioned.

Canvases that require special consideration are canvases that are on fabrics that lack the strong structure of traditional canvas 'duck' (from the Dutch word 'Doek' meaning cloth or linen). Vacation canvases are often of the least expensive upfront to the buyer, however they come with the hidden cost of requiring additional loving care because the fabrics they are painted on are made from what was available to the artist. Some of these fabrics might include leather, muslin, silk, or other blended fabrics, as well as poly canvases and vinyl canvases. Each of these have their own unique needs when being stretched to avoid damaging the piece.

While these types of canvases, are inexpensive to the artist and lower in cost to the buyer, the cost will be made up in the price of preparing the piece to be displayed. The artist is passing the cost of the presentation on to the buyer as an implied cost. This would typically be art found in destination locations and sold from kiosks or faires. While these pieces are often incredible in aesthetic, it is to be expected that getting them ready to show in your home will take a little bit of extra love. Leathers should be nail tacked, silks and other loosely woven fabrics will continue to expand after stretching and may do better with a keyed bar, muslin will require a gentle stretch to avoid the canvas tearing or changing shape

Can papers be stretched and displayed without glazing or glass like canvas? NO - contrary to some artists claims that you will not need to spend additional money to frame their piece under glass. Even if a paper is primed or treated, paper is made from a mache process that involves water and is hygroscopic. This means it will absorb passive humidity from the air, expanding and contracting like a sponge does when it comes into contact with moisture, and the attachment points will weaken without protection.

There are some wonderful papers on the market, Arches Oil Paper and Watercolor papers are amazing, and there are some really good sealants available, however NONE OF THESE are waterproof enough to protect the paper from it's own properties, nor are UV paper and paint sealants adequate to prevent fading and embrittlement of the paper. If the art is on paper, it will need to be handled according to its own individual properties. If a paper is made from wood pulp or mached fibers, it will require additional protection from dust, light and humidity when framed. If you could not wipe the piece down front and back with a damp cloth, the piece is not suitable to be framed without glazing. If the piece could not withstand a cascade from a jolted glass of wine or an ill timed sneeze, it requires glazing.

Large canvases and panels are a great way to display art!

Some fun vocab words to remember about canvas:

Stretcher bar - A strong, straight, wooden support made most often from pine, that has been kiln fired to assure that the bar has the needed hardness and is without twisting. Stretcher bars are keyed or otherwise have movable corners allowing them to be expanded as the piece ages to maintain the taught surface of the canvas.

Strainer Bar - A stretcher bar that is joined at the corners and does not expand.

Duck - The type of canvas cloth used in most modern canvases. Derivative of the Dutch word, 'Doek' meaning cloth or linen cloth.

Gallery Wrap - A canvas that has been stretched with the staples at the back of the canvas.

Standard or traditional stretch - A canvas that has been stretched with the staples on the sides of the canvas.

Tacking Edge - the border left around the art from which the canvas is secured to a stretcher bar via stapling.