An early 1990s reconstruction of the Iceman's head for National Geographic magazine shows Ötzi looking younger and healthier than the 20th-anniversary version.
For the older bust, John Gurche, an anthropologically trained artist, used anatomical data from Ötzi and modern European males, as well as his own interpretations, to flesh out the Iceman's face.
In a 2008 blog post, National Geographic editor Christopher Sloan, who worked with the reconstruction team, lamented that "we didn't have access to a three-dimensional cast of the skull. This was a severe limitation.
"Artist John Gurche had to reconstruct the skull from CT scans and photos before he could make his model."
Gurche, who is anthropologically trained, also used anatomical data from Ötzi and modern European males, as well as his own interpretations, to flesh out the Iceman's face, according to a 1993 National Geographic article.
Overall, Sloan noted, such reconstructions "make some people, particularly scientists, squirm. Why? Because they are primarily art. The reason is there are so many gaps in our knowledge that artists have to make guesses in order to complete the image."
(Related: "Wounded Iceman Made Epic Final Journey, Moss Shows.")