The Fantom postcard is believed to have of been printed by Hrvatski dnevnik in either 1937 or 1938 in Croatia. The below example is then completed and posted on the 17th of November 1942.
The printer of the postcard – Hrvatski dnevnik – is the same printer that released the first known solely dedicated Phantom comic as seen HERE
The stamp is from the NDH (Nezavisna Država Hrvatska) period of Croatia’s history.
The NDH (meaning Independent State of Croatia) was a World War II-era puppet state of Nazi Germany and Fascist Italy which existed from 1941 to 1945.
The stamp is from a set printed in photogravure by Tipografija d.d. and Hrvatska državna tiskara using a technique utilizing printing plates. The print run for this stamp set is from the 1st of September 1941 to the 7th of April 1943.
Stamps depicting various Croatian towns and scenery, were the first definitive issues in the Independent State of Croatia. The stamps were designed by Oto Antonini and Hinko Baranek, their initials can be seen on some of the stamps.