A mat is the paper-like material under the glass in a frame that is the border around your artwork. The mat typically sits on top of the image and the picture frame glass then rests on the mat. Depending how thick your mat is determines the amount of space between the frame's glass and your artwork. The picture frame size determines how big the outside of a mat should be cut and the inside measurements match the size of the artwork.
You do not always need to employ a picture mat. And there are no set rules about what will look the best. However, there are a few good reasons why you may want to consider mats as a nice addition to your piece.
Mats keep the picture glass away from the image. If the frame's glass is directly resting on the artwork there is a good chance that your piece of art may be ruined. Mould can form or the glass and the image may stick together because of trapped heat or moisture. If you would prefer to go without a picture mat you can try a 'frame spacer' that hides under the lip of the frame, keeping the glass away from the picture. The important thing is to let the air circulate in your frame!
There are a variety of mat colors, mat designs, and mat materials. They help draw the eye to the artwork and often enhance your picture. Mats help the piece seem important and suggests the artwork is worthy of a grand display. They provide an appealing setting in which art, documents, or photographs can be appreciated to their full potential.
Mats can help fit an image into an otherwise oversized frame by filling the space; while still achieving an aesthetically pleasing combination. Mats can rescue you from a framing predicament, and no one will know any different!
If your art is valuable, you want to make sure it doesn't get ruined over time, it is important to select acid-free mat board to help conserve your piece. This protects it from discoloring and destruction over time.