These magazines had various peculiarities compared with the standard American comic book.
Each issue had 48 pages, published twice a month, and for this reason Editoriale Corno decided to team up some other Marvel series inside the book. Typically 2 and 1/2 original stories were printed in a single issue.
l'Uomo Ragno had, as a partner in the magazine, various characters: Ant-Man, Dr. Strange, Hulk.
I Fantastici Quattro partnered with the stories of the "La Torcia umana" (Human Torch) taken from Strange tales, and later with Captain Marvel, Sub Mariner and a bunch of short horror and sci-fi stories.
The second peculiarity was that, since color printing was expensive, all these magazines had two color pages followed by two b/w (lineart) pages, then two color pages etc...
You could really admire the details of Kirby's, Ditko's, Colan's, Romita's etc. drawings, but I have to admit that back then, as a kid, I was not very happy about that. Now I absolutely love it!
Anyway, this is an example: the first two pages of the first FF annual, published in Italy in "I Fantastici Quattro 15" from my own collection (Annuals were not published separately, and they are not still today)
|I Fantastici Quattro 015 p1||I Fantastici Quattro 015 p2|
You can check the differences with the original US pages below. You can see that the Italian color pages were completely recolored with respect to the originals.
|FF Annual 01 p1||FF Annual 01 p2|
Speaking of recoloring, below are the same two pages taken from the Marvel Masterworks reprint series, recolored...
|FF Annual 01 (Masterworks) p1||FF Annual 01 (Masterworks) p2|
|Fantastic Four Special Edition 01 p1||Fantastic Four Special Edition 01 p2|
|Fantastic Four digital edition 01 p1||Fantastic Four digital edition 01 p2|