You may be surprised to learn that the earliest paintings at the National Gallery are the most likely to retain either all or a part of an original frame. Why? From the 13th century, when the Gallery's collections begin, on into the 15th century, it was typical for pictures to be painted on wooden supports. The panels on which the artist intended to paint included the frame, from the beginning, as part of the whole work. This larger structure was prepared before the painter even began to lay out the pictorial design or to apply the paint. In other words, pictures were framed before they were painted.
There are three different types of these early panel pictures with frames, which were frequently made by carpenters subcontracted by the painter: integral, semi-integral, and engaged.
For some small works that could fit on a single plank of wood, the flat surface for the painting itself was hollowed out from the central area of the plank, leaving a raised surrounding border to be carved and shaped into the frame. This type of frame, inseparable from the painted panel, is called an integral frame. The Gallery has a number of examples of these integral cornices in its Italian and northern European collections. Bernardo Daddi's Madonna and Child with Saints and Angels (1330s) in Gallery 1 has such a frame, although the delicate spiral colonnette embellishments and their capitals were added separately. Integral frames also surround The Crucifixion (c. 1400/1410) by the Master of Saint Veronica from in Gallery 35A, The Expectant Madonna with Saint Joseph by an unknown French master of the 15th century in Gallery 39, and Carlo Crivelli's Madonna and Child (c. 1490) in Gallery 13.
In one variation on the integral frame, the two vertical side members of the frame are carved from the same panel as the painting's support, usually running in the direction of the grain of the wood to make the carving easier. The top and bottom horizontal moldings are carved separately and attached by nails or dowels. This type of frame is called semi-integral. Unfortunately, the Gallery's collection contains no examples.
Far more common, especially on larger works, is the engaged frame. In this type, all the moldings for the frame were made separately and attached to the panel before the artist himself ever began to paint. Bernardo Daddi's towering Saint Paul figure from the 1330s in Gallery 2 is one example of an engaged frame. We can imagine an early stage in its production when the work was a large assemblage of planks and pieces of wood glued, nailed, and pieced together, with no paint. As in similar early panel pictures, once the work had reached this construction stage, the artist and his shop coated the entire assemblage, engaged frame and all, with gesso (a plaster-like substance mixed with animal glue that, once dry and carefully smoothed, provided the ground for the actual painting and gilding). Looking at the picture at an angle from the side, we can see the molding of the frame where it is attached to the thick panel, as well as the continuous seam where they meet.