The lens boards for the Graflex 23 cameras, both Century Graphic and Speed Graphic, are rather special. They are stamped aluminum, about 3/64 inch thick, 2-1/2 inches square, with rounded corners. They are dish shaped, and the part perpendicular to the lens plane forms a light trap with the interior of the camera. It would be difficult to duplicate them. These boards were once common, but they are now hard to find.
Originally Posted by zing