For The International Labor Bureau: Helvetia 70c Violet & buff

Regular Issue Overprinted

Country Switzerland
Denomination
?
Face value of a stamp, usually printed on the stamps.
— Glossary

70c
Color
?
Original catalog color of the stamp.

Violet & buff
Print method
?
Method of process of imprinting designs on paper.

Engraved
Perforation
?
Holes punched between stamps to make separating easier.
— Basic philately terms for amateurs

11 1/2, 12
Watermark
?
A pattern embedded in a paper during stamp producing process.
— Basic philately terms for amateurs

Swiss Cross
Issue Date
?
Date inscripted on a stamp or cancellation for used stamps not necessary correspond to real date of stamp issue.
#
?
Catalog number of stamp.
— Basic philately terms for amateurs