According to Guinness, the record is 20 hours for the temporary tattoos on Rod Steiger's entire body in the film The Illustrated Man, but there are many honorable mentions that came close.
In the 1969 movie The Illustrated Man, Rod Steiger plays a man whose entire body is covered in tattoos, each telling a story. The many intricate illustrations on his body took 20 hours to create, with 10 hours dedicated to his torso and the rest to the tattoos on his arms and legs:
The process was depicted in the 10 minute short Tattooed Steiger which is available on Youtube here.
- According to this, it took Lord of the Rings stuntman Greg Lane 16 hours to get into the makeup, prosthetics and costume of the torchbearer who blows up the Helm's Deep wall in The Two Towers. LOTR makeup work was frequently exhausting; according to the BBC:
As [Lawrence] Makoare has already recounted at the press conference, the scene in Fellowship where Lurtz is "born" under evil wizard Saruman's tower took 11 hours in the make-up chair.
- Eric Stoltz's transformation in the role of Martin in The Fly II was equally gruelling:
Martin [...] has begun to instinctively pull the webbing out of his own body and wrap it around himself. As it hardens, the webbing begins to form a cocoon. At this point, Martin's legs have been enveloped by said cocoon. [...] The most complex makeup, this stage took some 12 hours to apply to Eric Stoltz, and he was required to remain immobile on the motel couch (with his legs inside the partial cocoon) all that time, as well as during the additional hours of filming that immediately followed.
For me it was more like a modelling job because I had to put on all this special body makeup that took 13 hours to do.
The initial makeup work on James Marsters as Lord Piccolo in Dragonball: Evolution took 17 hours as James insisted that Piccolo look old, but this was scratched and later significantly shortened (However, that initial figure changes to 14 hours in a few places).
Rick Bottin's work on actor Robert Picardo in the cult 1981 werewolf film The Howling forced him to spend either 10 hours or 13 hours in the make-up chair (depending on the source).
Once again [Jack] Pierce meticulously glued strand after strand of yak hair onto Chaney's face, hands, and feet. Pierce received a powerful assist from Universal's special effects ace, John P. Fulton who supervised the excellent transformation scenes. This was achieved by keeping Chaney pinned in position so he couldn't move and setting targets for his eyes so he could hold them still. The camera was weighed down with a one ton weight to likewise keep it immobile. Then five to ten frames of film would be shot, after which Pierce would apply more makeup, and another five to ten frames of film would be shot, and so on until after 22 hours of filming, the transformation was complete. Quite an ordeal for Chaney who would mutter threats about wanting to kill [Curt] Siodmak for having conceived the Wolf Man in the first place!