Background: we had an old painting my wife's aunt had done many years ago. Somehow in its travels it managed to acquire an inch long tear, no doubt from something poking it. The painting wasn't valuable in a monetary sense, but it had sentimental value. I said I'd repair it.
Before going much further I consulted the source of all wisdom, my ancient copy of Ralph Mayer's Artist's Handbook of Materials and Techniques. Among the chapters is one on conservation, which includes a section on repairs. It became my road map for this project.
