-ray image in restoration is most commonly used to see how the artist originally the composition of the painting. Thjs is relevant as paintings of a certain age tend to have undergone previous restorations, overpaintings and changes to the composition itself. Such drastic restorations were popular from 19th Century up until the first quarter of the 20th Century.
It is at times possible to bring back certain details that have been overpainted, or are simply missing due to abrasion. If an X-ray image shows that enough of an original paint layer is still intact, a later overpainting can be removed, to uncover the original. This should only be done following careful consideration of the technical and ethical implications.
Reconstructing a painted area back to how the artist originally intended it, is often done when the painting is visually unbalanced. In the example of the painted sleeve shown on the left, it is clear that without a reconstruction of the folds, an otherwise perfect 17th Century painting composition would be lacking in style and appeal.