Should an Oil Painting be Framed Under Glass?

Discover Why Glass Isn't Always Necessary

Is it recommended or necessary to frame an oil painting under glass? While not necessary and rarely used with oils, there are a few instances in which you will want to add glass to your frame.

Should an Oil Painting be Framed Under Glass?

There is no need to frame an oil painting under glass if it's painted on canvas, panel, or board. Glass is used in framing to protect the artwork from moisture and harmful UV rays which can fade the colors.

 The final varnish applied to oil paintings is often considered sufficient protection. 

Remember: An oil painting shouldn't be varnished for at least six months after it is finished to ensure the paint is thoroughly dry.

You might notice a few oil paintings behind glass in a museum or gallery. This is used primarily as extra protection against vandalism for very valuable works of art. Sometimes, a special grade of glass - often called conservation or museum glass - is used to add even more protection from light and some glass includes a coating that reduces reflections as well.

While it is not necessary to frame most oil paintings with glass, there are a few exceptions. If your painting was done on paper or thin card, adding glass to the frame will protect the support. The oil paint itself does not need the protection, but the paper does.

If you do decide to place an oil painting behind glass, be sure to include a mat (also called a framing mount).

Mats are important elements to framing and it goes beyond adding a nice decorative touch. 

A mat is essential because it adds space between the glass and the artwork, which is why they are often used with flat work like photographs and watercolors. This extra space allows air circulation and prevents condensation that can lead to mildew, mold, or buckling.

For paintings, the mat also ensures that the paint does not touch or stick to the glass. If your painting has thick paint, make sure the matting is thicker.

Options for Framing an Oil Painting

Since glass is not recommended, how do you frame an oil? There are many framing options available for oils on canvas, board, and panel: 

  • Attach a frame to the front of the canvas.
  • Mount the canvas or board into a floating frame.
  • Skip the frame completely (often called a gallery wrap). You need to ensure that your canvas is very neatly wrapped and may want to continue your painting onto the canvas that covers the side rails.

Types of Paintings That Should be Framed With Glass

Oil paintings are one of the few types of paintings that do not require glass when framed. Varnished acrylics also follow the 'no glass' recommendation. If you work with other mediums, it is important to know what type of framing is recommended.

Artwork for which glass is recommended:

  • Any work on paper or a similar thin support.
  • Pastels and watercolors.
  • Drawings in pencil, charcoal, and similar (very vulnerable) mediums.