Re-learning how to stretch canvas

After switching to heavy pre-primed linen several years ago, stretching new canvases (usually one of my favorite studio jobs) became difficult. I was getting little sags at the corners that refused to go away, sometimes even after attempts at re-stretching. And when things did go well the amount of effort required with my standard canvas pliers was almost brutal. After several exhausting sessions resulting in sore fingers and disenchanted studio assistants, I went looking for a better way. To my surprise, I found out that this humble part of the studio practice is being revolutionized.

First, I found this:

That’s a canvas stretching machine in action. This is just one of several different models, all working on basically the same principle, and for the same end. That end is stretching ink-jet art that has been printed on canvas. Although there is something a little bit sinister (from a painter’s perspective) about all that machine-printed canvas being framed up out there, this sure looks easier than what I was doing. 

Of course, it would be hard to reconcile the $4000-$8000 price tag with the light volume of stretching I require, and finding room for more equipment would be a problem. So.

Then I happened upon an article in the Golden Paint Company’s newsletter titled A Remarkable Way to Stretch Canvases. In the article, San Francisco based conservator James Bernstein describes how the procedure traditionally taught in art schools gets the business of stretching a canvas almost backwards. The simple but radical change change that Bernstein suggests is that stretching be done starting from the corners of the canvas and proceeding towards the middle, rather than tacking the middle and then working outward as is traditionally done. Here’s an example of a version of the old way on Utrecht’s website. The explanation in the Bernstein article is very clear, so give it a read.

The article goes on to explain how results can be improved further by using tacks to attach the canvas while you even out the tension. Bernstein suggests waiting a day or so while the canvas adjusts to the tension before doing the final stapling. This really works great. As noted in the article, the quality of tacks makes a big difference. Go buy yourself some new ones- you will want them to be sharp and strong. Look for tacks with aluminum heads and steel points.

You will also need gloves that protect your fingers while still allowing you to handle the tacks. The nitrile-coated, knit-type of glove worked well for me, and they are cheap and easy to find.

Following Berstein’s hint, I also went looking for a better pair of canvas pliers. I had tried pretty much everything available at the art store, including a pair of  expensive Holbeins loaned by a friend. Poking around Google eventually brought me to the modified pliers sold by Twin Brooks Stretchers. These heavy-duty pliers have the advantage of compound leverage. Where most art store pliers have one pivot bolt, these have four. This means that less squeezing is necessary to keep the canvas from slipping. The sharp, welded-on leverage bar works well. In fact the problem--if you want to call it that--is that these pliers are strong enough to damage either the canvas or stretcher bars if used carelessly! Similar pliers are also available from John Annesley in San Francisco, who offers several different styles aimed at different stretching problems. I have found that the standard version offered by Twin Brooks works well for stretching the five and six foot canvases that I favor, and I liked working with a relatively local company.

The final element in the canvas stretching revolution was the purchase of a simple digital thermometer/hygrometer for the studio. As Berstein explains in a separate Golden Paint Company information sheet titled Environmental Conditions for Successful Canvas Stretching observing the current conditions in the studio and timing your efforts accordingly can save headaches down the road. Although the relationship between temperature and humidity and canvas tension is complex, Bernstein points out that canvas will generally be more pliable at higher temperatures. The information sheet packaged with the Claessens linen I have been using suggests stretching at low ambient humidity. Happily, that combination is easy enough to achieve in a dry, mid-winter Brooklyn studio by simply cranking up the heat. It will be interesting to observe the difference when the next batch of new canvases gets stretched under more humid conditions later this year.

Here’s a photo of  the Twin Brooks stretching pliers in action, re-stretching an in-progress canvas using Berstein’s method, observation of environmental conditions, and tacks: