There is a common misconception which still abides today regarding Garamond typefaces: that all Garamond types were based on the typefaces cut by Claude Garamond in the sixteenth century. In fact, the Garamond label is quite often a misnomer, as many of the Garamond fonts in existence today were in fact modeled after a later contributor to the world of type: Jean Jannon.
Jannon, an engraver by trade, was born in 1580 in Switzerland – exactly one century after Garamond and nineteen years after the famous publisher’s death. His typographic life began after he decided to create his own type to avoid having to have an alphabet shipped from Paris or Germany which at that time was quite difficult. His existing type was also wearing out; a brand new typeface was finished around 1615, based on the Garamond of the previous century.
Thus, the confusion around Garamond and Jannon began. Misidentification of the Jannon type as Garamond’s work, while flattering, was later proven inaccurate. Therefore the many Garamond variations in existence today are often based on Jannon or are a typographical hybrid of the Jannon/Garamond types.
However, the Stempel Garamond font was based on a 1592 Garamond specimen by printer Egenolff-Berner, so the inspiration for it was indeed the original engraver and not Jannon. The Monotype Garamond™ font family, released three years earlier (1922) is an example of a Jannon-based typeface.
Reference:
Linotype: Just What Makes A “Garamond” a Garamond?