Stretching Pre-Primed Canvas

[Garth Herrick]

Here's some info I just posted over at the nell'arte forum, over the question of how to deal with the difficulty of stretching oil pre-primed linen, and I thought it would be useful here too in this Forum:


When you are using the canvas pliers on pre-primed linen (Garth's personal method):

1.) First make sure your stretcher bars are secured with temporary screws in each corner to keep them from slipping out of alignment or out of square (this will invariably happen if the corners aren't secured). You will remove those screws again when you are finished, so that the keys you tap into the corners can do their job.

2.) Start with stretching accross the shorter dimension, then the longer one. This aids in spreading the tension more evenly taut. Get these pulled very taut, or you may have to reset them more taut on a second try. Doing this, get the canvas positioned and tacked on all four sides, with just the first tack in the center of each stretcher.

3.) Next stretch temporarily to each corner, pulling firmly, and tack temporarily to both sides of each corner (8 tacks total). The reason for this step in the procedure is to pre-condition the pre-primed canvas to behave better in horizontal tautness along the stretcher bar. Without doing this, you will tend to find tension bunching ripples toward the center of each side in the finished canvas, which can't be doctored or removed. This tendancy is always more severe accross the longer dimension, due to the more severe angularity of the stretching tension.

4.) Now you can proceed as usual adding tacks outwards from the center, short dimension first, then long dimension. You may speed things up along the short dimension/long stretchers by adding two tacks to one on the short stretchers, until each row of tacks is made even distance from the corners. IMPORTANT: For evenness of tension, as you pull the canvas taut with the pliers, you must take extra care to match the tension you previously pulled for the last tack... no more and no less! A change in tension will leave a subtle but permanent tension ripple as an artifact of your technique. The way you can judge if the tension is correct is by observing the canvas behavior just in front of the previous tack. If the canvas starts to bunch up before that tack, then you are stretching too taut, etc. Only place one tack with each pull of the pliers, even though the pliers are so wide. Two or more tacks with each pull is asking for uneven tension trouble.

5.) I bet you all know the rest!

You should get excellent, ripple free [drum -tight] results by this method, with the most unforgiving of pre-primed canvasses.

Happy Stretching,

Garth