The Saint Matthews and Ezra Prototype?

The author portrait of Saint Matthew, from the Lindisfarne Gospels and the portrait of Ezra from the Codex Amiatinus can be easily compared since both are of similar nature. They can be compared for similarity and differences in the elements of frame, background, position and composition of the central figure, rendering of drapery, perspective and dimension, the use of line and pattern and the suggestion of space and environment. Though the two portraits may exhibit some differences, it is generally thought that they were both copied from a common prototype and there is much evidence to support this.
The similarities begin from the very outset and can be seen in the frame of these two portraits. In both portraits, the frame surrounding them are rectangular. In both, the outer frame consists of a thin border and is colored red. Further, there is an emphasis on the corners of both portraits. In the Saint Matthew portrait the emphasis is in the form of a intricate design, the center of which is colored with gold. The corners of Ezra's portrait does not have a design but it is colored gold, an expensive color showing the emphasis of the artist on the corners. The borders of both outer frames are black straight lines ending in squared off corners where the respective emphasis is located.
…