Shortly after a painting is torn, distortions in the canvas set in and realigning the edges of the tear becomes progressively more difficult. A tear is best left untouched except by a conservator. If emergency mends must be applied to the reverse of the painting, pressure sensitive tape, such as Scotch or masking tape, must be avoided. Causes Tears usually occur due to unsafe storage or manhandling. Treatment A conservator must consolidate any flaking paint along the fractured edges of a tear and then proceed to align the canvas threads and paint film. Loose threads must be adhered from the reverse. Sizable losses are compensated for with canvas inserts that must also be adhered into place. If the tear is very large, the painting may require a lining (refer to weak canvas).