At the same time, the 100-franc note is the most frequently counterfeited in Switzerland. Most forged banknotes lack the security thread and the watermark. The security thread is visible when the note is examined in backlight. The watermark can be spotted the same way; it is arranged on the white part at the obverse of the notes: backlight will reveal the respective portrait of each note. On the one shown here, it is the architect Francesco Borromini from Ticino.