NOBODY should be surprised that the two young actresses who starred in Abdellatif Kechiche's Palme d'Or winning film, Blue is the Warmest Colour, told an interviewer at the Telluride Festival last month that filming the explicit 10-minute lesbian sex scene was "very embarrassing".
Four months after their triumph in Cannes, Lea Seydoux and Adele Exarchopoulos confirmed what many must have guessed anyway: shooting a sex scene over 10 days in front of a director and a film crew is gruelling and not very much fun.
Watching it with your parents afterwards isn't much of a riot either.
The actresses' comments about Blue is the Warmest Colour came in the week that the casting was finally announced for Sam Taylor-Johnson's adaptation of E L James's 50 Shades of Grey.
Charlie Hunnam and Dakota Johnson, the two relative unknowns chosen to star in the 50 Shades movie, should be very wary about what their roles might mean to their careers.
It has long been the ambition of both European and Hollywood filmmakers to make films that deal in a serious, sensitive and artistic fashion with sex.
The problem is that the prurience of producers and audiences alike invariably gets in the way. The actors are usually the ones who suffer as a result.
"In the 70s, there was a kind of dream that there would be a crossover film that was both explicit and a solid film," Paul Schrader suggested in Venice last week when he presented his new feature The Canyons, starring Lindsay Lohan and porn star James Deen.
"I think that dream was a false dream and I don't think that that crossover film will ever, ever occur."
Schrader added that "the part of our brain that responds to explicit imagery is a different part of our brain than what responds to long-form narrative".
Would you shoot or be shot in a sex scene?
This poll ended on 08 September 2014.
I'd do either
I'd shoot but not be shot in one
I'd be in one but someone else can hold the camera, thanks
You wouldn't catch me dead in either role
This is not a scientific poll. The results reflect only the opinions of those who chose to participate.
It's a paradox that so-called "adult movies" are made in a thoroughly juvenile way. In these films, character development and plot are expected to be flimsy in the extreme.
After all, that is not what the audiences are interested in.
The problem for mainstream actors in an internet age is that sex scenes in "serious" movies are bound to be taken out of context and posted online alongside the porn.
Women almost always fare the worst.
Take Bernardo Bertolucci's Last Tango in Paris (1972). The critical consensus is that it features one of Marlon Brando's greatest performances as the despairing middle-aged American who has an anonymous sexual relationship with a much younger woman he meets while looking to rent a Paris apartment.
For the young actress Maria Schneider, though, the film was a disaster.
"Poor Maria. I didn't have the occasion to go to ask her to forgive me a bit because her life was completely swept away by Last Tango in Paris," Bertolucci said recently of Schneider, who died in 2011.
He acknowledged that he may have "robbed her of her youth". In that infamous scene in which Brando's character sodomises Jeanne (Schneider) using butter as a lubricant, there is little wonder that Schneider looked so incensed.
Neither the director nor Brando had told her what they were planning.
Whether Margo Stilley and Kieran O'Brien in Michael Winterbottom's 9 Songs, Kerry Fox and Mark Rylance in Patrice Chéreau's Intimacy, Julie Christie and Donald Sutherland in Nic Roeg's Don't Look Now or Anne Heche and Joan Chen in Donald Cammell's Wild Side, there are many films in many different genres in which very frank sex scenes are treated in non-sensationalist fashion.
Even so, actors need to take an immense leap of faith when they agree to appear in such scenes.
They are often in a weak position vis-à-vis the filmmakers who are asking them to perform. They may need the work.
They may not fully understand the director's vision.
Keira Knightley admitted that when she was offered the part of Sabina in David Cronenberg's Freud/Jung film, A Dangerous Method, she initially turned it down because of the nudity and her character's masochistic tendencies.
Cronenberg offered to take out the more extreme scenes but she realised (as she explained in an interview), that it was "important to see that shocking, brutal thing that was happening within herself… what she [Sabina] wants, what has torn her apart. You do need that visualised."
Cronenberg is a respected auteur. So is the Danish maverick Lars Von Trier, whose supposedly explicit new feature, Nymphomaniac, is due to premiere in Copenhagen in December.
Starring Charlotte Gainsbourg and Shia LeBoeuf, the film looks at "the erotic life of a woman from the age of zero to the age of 50".
Von Trier's associates have been at pains to point out that the film is being targeted at a female audience, not at voyeuristic, porn-obsessed males.
The director's business partner, Peter Aalbæk Jensen, recently commented that the "sex element" is the least interesting aspect to Nymphomaniac. "It's much more fun than expected ... for a female audience who we normally scare away if we have too much kinky sex, I think they will love this film because we are dealing with a complete heroine. It's a woman stronger than everybody around her."
Von Trier has avoided potential embarrassment for his actors by using body doubles (to show characters having sex from the waist down).
Big-name stars relish working with the Danish filmmaker because, as Willem Dafoe, also starring in Nymphomaniac, puts it, "he is one of those people that gives so much to what he does. I appreciate that. Superficially you could see him as smug or clever or working it, but on some level, he's very sincere. He is just a very conflicted artist and he likes to challenge himself."
In other words, when a director like Von Trier is ready to push to extremes and risk humiliating himself, the actors are willing to fall in line behind him, even when it means depicting sex on screen.
That wasn't the case with the distinguished French filmmaker Jean-Claude Brisseau, who ended up in court after two actresses accused him of sexually harassing them during the auditions for his film Secret Things.
He was found guilty but was unrepentant. "These erotic auditions are indispensable... they allow me to find out qualities and problems with their bodies and their acting," he stated.
It remains to be seen what ordeals Charlie Hunnam and Dakota Johnson will face at director Sam Taylor-Johnson's hands while making 50 Shades of Grey.
If Taylor-Johnson wants to avoid the Brisseau syndrome or the backlash from the cast of Blue is the Warmest Colour, she should pay attention to the example of Steven Shainberg when he was making his sprightly S&M film Secretary, starring Maggie Gyllenhaal and James Spader.
He accentuated the humour and the intimacy, billing the film as a battle-of-the-sexes comedy, and moved away from the heavy breathing.
The end result? No one was embarrassed and the actors didn't grumble afterwards.
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