Most directors and producers want to make their movies as realistic as possible. Whether making a gritty action film, romantic comedy, or terrifying horror movie, they want audiences to believe what they're seeing is real. Such credibility comes from many factors, and requires the performances, script, and other facets to be top notch, to ensure viewers don't lose interest. One of the biggest aspects of maintaining believability in a theatrical release is special effects; if a film can't replicate what people see in daily life, or create credible alternate realities, that movie quickly lose authority.
Although people generally think of special effects as explosions and CGI, the truth is, prop designers and FX experts are involved in the effects process throughout the making of a movie. They especially come in handy when the filmmakers need a nasty substance. After all, you can't expect your cast to actually bleed, or wade through raw sewage (unless you're Neill Blomkamp), even if the script says just that. So the effects team has to come up with safe alternatives. A lot ingenuity goes into gross things used as props in films, especially things used for gross substances in movies (puke, for instance).
If you've ever wondered "what do they use as blood in movies?" or how filmmakers recreate vomit, snot, sweat, slime, ejaculate, and more, read on: you’ll be amazed by the creativity and resourcefulness of those responsible for creating special effects.
Colored Water Substitutes for Raw SewagePhoto: 20th Century Fox
Having something a little less smelly and disgusting than raw sewage is a godsend for cast and crew. One of the most memorable scenes in Star Wars: Episode IV – A New Hope saw Han, Luke, Leia, and Chewbacca trapped in a garbage compactor filled with junk and sewage. Roger Christian and John Barry found that water mixed with dark food coloring made the perfect substitute for a stew of human waste. Those on set didn’t have much fun, though, as the hot studio lights and material used to make trash caused the water to stink after a few days. Peter Mayhew, who played Chewbacca, had it worst - the stink seeped into his costume and stayed there.
Everything from Oatmeal to Soup Is Used for VomitPhoto: Universal Pictures
Vomiting has become a staple in movies. Whether it's an eruption of projectile vomit or the tiniest little bit of puke, prop designers and special effects crew often fall back on tried and tested methods when puke is needed in a film. A common substance used to simulate vomit is oatmeal, though movies like The Exorcist and Monty Python’s The Meaning of Life used pea or minestrone soup to get the desired effect.
Rotten Fish and Seaweed Used for General DirtPhoto: Universal Pictures
Oscar-nominated production designer Eve Stewart wanted to remain as faithful to Victor Hugo’s Les Miserables as possible when it came to the 2012 film adaptation. She wanted everything to feel as realistic as possible, and to channel the atmosphere of the story onto the screen. When it came to designing the sewer, and having dirt and mud everywhere, Stewart used rotten fish and seaweed to get the desired effect. This made life difficult for Anne Hathaway and the chorus, who shot for several days in a very smelly environment. In Stewart's words:
In Pinewood, in the studio, the set that we made where Anne [Hathaway] sings "I Dreamed a Dream" absolutely honked; it was so stinky because we had real fish that would slowly go off under the lights. And then we brought all this seaweed down from Scotland, and that stank. But a lot of the chorus appreciated the fact that they were made to feel really cold in this dripping, stinking hole, and it brought it to life for them how they would have to survive.
The Marshmallow Goo in Ghostbusters Is Shaving CreamPhoto: Columbia Pictures
Ghostbusters required plenty of ingenuity on the part of its special effects team and prop designers to achieve all its goo, slime, and general nastiness. The biggest job came with the explosion of the Stay Puft Marshmallow Man at the film's climax. The sticky white substance looks remarkably like melted marshmallow, but was in fact around 50 pounds of shaving cream that had been thrown on the set and various scale models. Between the shaving cream and Methyl Cellulose, Ghostbusters sure does have a lot of sticky white stuff flying around.