The large prototype Superman head shown above was created by a Kenner sculptor using two different mediums: wax and carbalon. It can essentially be considered *the* master sculpting for the head of a pre-school style plush Superman, which never saw production. At least one complete prototype sample was crafted as evidenced by imagery from existing Kenner file photography shown later in this entry. The head used on that sample was likely crafted using a silicone mold made from the prototype shown in this entry. As such, the sample's head would have been cast completely in urethane and entirely hand-painted.
The head is cast in a tan colored urethane referred to as carbalon. The head was originally sculpted completely in wax with a more serious look, however management requested a softer, more cartoonish face, so an unpainted hardcopy of the initial incarnation was re-worked using alterations accomplished in sculpting wax. The bulk of the changes reside in the eye, mouth, and nose regions although some sculpted revisions also exist along the ear/hair regions. The close-up image shown above zooms in to demonstrate the major refinements that were accomplished by hand using sculpting wax.
The 4th and 5th photos show the prototype from both side views. Wax refinement above the ears is visible in these two photos.
The 6th photo offers a bottom view of the prototype Superman head.
The above composite image show a complimentary Kenner file photography slide (front & back) that also resides in my personal collection along with an enlarged version of the actual image contained on the slide, which I personally generated by digitally scanning the slide that I own. Additional file photography images are available for viewing here on my website. Sadly, the complete prototype sample has not surfaced to my knowledge, so it's quite possible it no longer exists. On the bright side, thankfully the master head survived the test of time thanks to an ex-Kenner contact's foresight.