These amazing sets of four glass plates were used to create the 1935 and 1936 US Christmas Seal Negative Maker's proofs. NM proofs were created after the artist's work first became a single die proof; a single, or sometimes pair or block of seals surrounded by a large white margin. NM proofs came next, a full pane, usually 100 seals, surrounded by a large white margin. NM proofs were used by all the regional printers of Christmas Seals to create massive press sheets which were perforated and cut into single panes, and sent to every family in America.
The other side of these glass plates are expertly touched up to insure solid colors on the final product. Forgive the terrible reflections in these pictures. I imagine most production items like these have been lost to time. I have seen only one or two other sets of glass NM plates from the 1950's.