I stretch primed cotton canvas on 2ins x 1.5 ins stretchers, no keys, approx; 1.5 metre x 1 metre. The problem is when I move the painting to a more humid environment, ie, an area with underfloor heating the canvas warps.
I have tried spraying the back with water and it returns to it's original taut position. However, when I move it to a more humid location the warping re occurs. How can I fix this.?