Frames can display paintings with or without a protective glass covering. Ultraviolet filtering glass is sometimes placed over the painting to protect the painting surface from harmful ultraviolet light and also from dirt and fingerprints. Although a sheet of glass definitely protects the surface of a painting, it also changes the appearance of the painting. The aesthetic effect of a glass covering should be considered along with its protective qualities. If you have any questions about your painting, a paintings conservator can help you.
Paintings conservators are professionally trained individuals with years of experience.
You should solicit the advice or services of a conservator any time that you have questions or concerns regarding a painting. The John Paul Getty Museum, 1992. Dover Publications, 1966. A Handbook on the Care of Paintings , The American Association for State and Local History, 1965. Columbia University Press, 1948.