Mixon didn’t start designing the Pennywise makeup until after Curry had already been cast. Using a copy the actor’s photograph, he started penciling out a few ideas. This was followed by a standard practice of making a full plaster cast of the actor’s head. Prosthetics-based makeup will require such casts for the artists to sculpt rubber and silicone pieces that will fit the actor precisely. When sculpting onto Curry’s plastic head, Mixon thought of one famed movie monster in particular. He said:
“Once I got Tim’s headshot, I did a tracing of and started making various design sketches. We also made a head cast and designed three clay sketches so we could see how the design would look in three dimensions. The basic inspiration was Lon Chaney’s ‘Phantom of the Opera,’ stylized into a clown.”
In Rupert Jillian’s 1925 feature film “The Phantom of the Opera,” based on the 1910 novel by Gaston Leroux, Lon Chaney played the title character, a sewer-dwelling organist whose face had been mutilated, and which he hid under a mask. Chaney created his own makeup for the role, stuffing wadding in his cheeks, adding black skeletal highlights around his eyes and lips, and inserting wires up into his nose. The result was something more ghastly than a typical death head. To this day, it remains one of the more striking makeup jobs in cinema history.
Seeing as how the Phantom was a sewer-dwelling monster, Mixon followed that Pennywise should evoke that. Notably, Chaney’s upturned nose was incorporated.