Genuine

Forgery
Gooding #4F1. The line shading on Isabella's hair and neck shading terminate cleanly into a wave pattern. "FRANCO" is shorter than the genuine. There are more horizontal shading lines and they are so close to each other. More pearls around Isabella.

Bartels #C4.1; Earee Second Forgery (Page 208)

Gooding #4F2
Text in wrong position. Isabella has no clear neck as the shading lines end abruptly and the shading inside the neck in thick lines which extend close to the Isabella's mouth. 

There are also fewer horizontal shading lines. The pearls larger than on the genuine stamp.

Large pearls, the number of around Isabella
less than in the genuine stamp.

Bartels #C4.2; Earee First Forgery (Page 208)