Post by Twintle boss

WHY do museums keep some paintings under glass while others don't?

Traditionally, oil paintings are exhibited without glass. The painting is normally coated with a transparent varnish, which makes it resistant to exposure and allows for wet cleaning. Graphics are usually displayed under glass, as pencil, watercolor, ink and pastel are easily damaged and almost impossible to clean.

In some cases, oil paintings are also protected by glass. For example, against fading due to ultraviolet light or when cracks in the paint prevent wet cleaning, as well as in cases of special value and threats of vandalism.