The first printings made between 1966 and 1968 were done with photogravure cylinders prepared by the "private industry" as they say instead of made/prepared by the Printing House itself in Paris.
The printing house at Boulevard Brune in Paris had just started printing in photogravure on the HEL-1 press made by Chambon,.
What makes this stamp so important is that - not yet assured but ... this could have been the first stamps printed by cylinders made in EME! Elecro-Mechanical Engraving years before the Belgian stamps printed in 1982!
The French have not yet started to study this stamp again so we need material - with margins - in orde to check whether EME was in use or still the traditional etched cylinders!
