The purpose of this screen is to allow the viewer to compare multiple copies of the same postmark type.
Obviously, our collection is small at this time. Hopefully, someday there will be more postmarks to compare.
1/2 line at top of bottom moon; This postcard was printed in Vatican Notes, Vol 67, Issue 383, page 46
No lines to separating moons, ink mark on first three perfs of lower left stamp corner suggest might be a partial line