In the highly informative series Conservation Stories by the The Museum of Modern Art, conservator Diana Hartman explains the step-by-step process she uses to repair holes in stretched canvases using the painting “Self-Portrait with Two Flowers in Her Raised Left Hand” by German artist Paula Modersohn-Becker. The delicate 1907 canvas was showing signs of wear along the frame, which Hartman re-weaved using an ophthalmologic needle, surgical sutures and threads stiffened with glue from sturgeon swim bladders.
What I’m going to do is apply a little of the sturgeon glue adhesive to the linen thread in order to stiffen it just a little, so that it has a little bit more stability. The method of tear repair here involves actually reweaving the little canvas threads back into the original woven pattern in order to basically microscopically darn a hole in a canvas.
