Updated October 12, 2018
Often when I stitch an older canvas I’m stitching it in hand. Stitching them got me thinking about canvas.
High-quality canvas, like Zweigart mono, is made from 100% cotton. The stiffness of a new needlepoint canvas comes from sizing added to the canvas once it is woven. Sizing also makes canvas hard on threads because the stiff sizing wears out the thread more quickly than the smooth fabric alone.
Sizing is removed from canvas is several ways, not that you would set out to do this initially. If you thoroughly wet the canvas, you notice it’s a bit sticky — that’s the sizing. Wet it and wring it out a couple more times and the sizing is removed.
As you stitch the canvas, your needle moves the canvas back and forth – this will eventually break down the sizing. Folding the canvas also does this along the fold. When canvas is finished or blocked with water, the sizing disappears.
If you paint or dye the canvas and use too much water, the sizing gets removed.
Finally, the sizing disappears as the canvas gets old even if it has just been sitting around..
Sizing is actually a type of starch. Just as starch washes out and starched clothes get softer as they are worn, sizing does the same things.
In my case, on an older piece the canvas was folded (and I know better) and it is three years old. So it’s very soft. I’m still crumpling it up in hand, so I don’t mind too much, but if you have an old canvas and want stiffness, your only solution is to stretch it on a frame. Stretching and the tension it brings will put stiffness back into the canvas. I would go further and say just use Evertite bars because you will need to adjust the tension more often with an older canvas. One caution though, your stitch tension is different on stretched and unstretched canvas. If you choose to stretch a partially stitched canvas, be aware of this and make adjustments.