Unlike oil paintings, which are strong enough to be framed without a mount, other artistic techniques such as water colours, etchings or photographs require a space between the picture and the frame. Otherwise, even a slender moulding would give the picture a confined, oppressed feel.
The mount not only puts a distance between the picture and the moulding, but also effects a smooth transition. Especially for smaller pictures, it creates an area of calm around the motif, guiding the viewer´s attention towards it. This is necessary because smaller works have to be viewed from close up. Humans can only zoom in to a limited extent on one object. Without a mount, the picture, the frame and the surrounding wallpaper would all have to be taken in at the same time.
Even a simple paper mount can fulfil these functions. Thicker mount boards are used to prevent contact between the picture and the glass. During long periods of bad weather, with high humidity, the paper within the frame absorbs water from the air which is then trapped inside the frame. If there is no mount or it is too thin, this can lead to stains on the picture caused by mould or mildew. For thicker mounts, a slanted cut guides the viewer’s eye towards the picture, accentuates the depth of field and simply looks better. This is called a bevel cut mount.