Is there any way to fix the ripped Picasso? Yes, but it will be slow and tedious work. The torn ends of the canvas can probably be lined up, and conservators can identify matching fibers on either side of the rip by inspecting them under a microscope. In general, you can expect the wefts in the fabric—that is, the crosswise yarns of the weave—to split at the site of the impact. The lengthwise warps tend to get stretched out, but they may not break.

The rip itself can be mended in a few different ways. First, the conservator can line up the torn ends and affix them to a new piece of fabric that lines the back of the painting. She might also try to attach the torn ends to each other using a method called Rissverklebung, in which individual fibers are rewoven back into place.

To reweave the warps and wefts, you have to figure out the proper placement of each individual fiber. Bits of paint that are stuck to the fibers must be glued in place or removed until the reweaving is complete. (Conservators map out the location of each paint flake they remove so it can be replaced in precisely the right spot.) Because an accident will stretch out some fibers and fray others, you sometimes have to tie off and shorten some threads while attaching new material to lengthen others. Threads attached to the back of the canvas will reinforce the seam.

Closing the tear is only the first part of the process. An accident like Wynn's can damage the painting in other places by stretching the fabric and distorting the image. To correct for these planar distortions, the conservators try to change the lengths of individual fibers or small patches of the canvas. Applied humidity can make a fiber expand across its diameter and shrink across its length—and tighten up distended parts of the weave.