The lining of paintings is a process of conservation science and art restoration used to strengthen, flatten or consolidate oil or tempera paintings on canvas by attaching a new support to the back of the existing one. The process is sometimes referred to as relining. Most often a new support will be added directly to the back of an existing canvas. In cases of extreme decay, however, the original canvas may be completely removed and replaced. The height of the practice's use peaked in the late 19th century and in the following years its usefulness has been debated.[1] There are many different factors that influence whether lining a painting will be successful. By paying close attention to an artwork's condition and response to treatment, conservation professionals better understand the lining process and when to apply it.[1]