In the 21st century, cinema and film play a major role not only in our social activities, but also as a tool for learning about our history, addressing the issues faced in society and imagining what the future of a more innovative world would look like. However, the legal implications of telling a story through film, the cinema and television, go far deeper. Issues of copyright infringement, particularly within the Hollywood and Bollywood context, have found their way to the court room.

A recent blog post entitled "Bollywood and Copyright – Infringement or Inspiration" by Indian law firm Selvam and Selvam shines a spotlight on this issue.

The argument in the post is that Bollywood films have for too long blatantly copied Hollywood films. Whenever Bollywood filmmakers are challenged on this, they claim that, although they may have been inspired by the Hollywood film, they haven't actually copied it. Examples of Hollywood films that have been used as "inspiration" for Bollywood films include Knight and Day (starring Tom Cruise and Cameron Diaz), which became Bang Bang; Hitch became Partner; Reservoir Dogs became Kaante; and My Cousin Vinny became Bande Yeh Bindas Hai.

But Hollywood is fighting back. Twentieth Century Fox has successfully sued Indian filmmaker Sohail Makla Entertainment for infringement of copyright in the film Phone Booth (starring Colin Farrell), and it has even been awarded damages. Apparently, the Bollywood film Knockout has an almost identical plot involving a hostage in a phone booth, who is in telephonic contact with a sniper, as well as the usual side-shows such as extra-marital affairs.

What cases like these focus on is an issue that is sometimes referred to as the "idea/expression dichotomy". This is also expressed in the phrase "there is no copyright in ideas". What this means is that, although copyright protects the material expression of ideas – the book, the film, the record – it doesn't protect the ideas per se. There is also a principle that copyright is only infringed if a material part of the work is copied. These things may all sound fairly straightforward, but they're not always so easy in practice.

The Indian Supreme Court has said that the test regarding idea/expression and substantial part is to "see if the reader, spectator or viewer, after having read or seen both the works, is clearly of the opinion and gets an unmistakable impression that the subsequent work appears to be a copy of the original." The blog post ends with these optimistic words: "We're slowly reaching a stage where infringers will not be able to hide behind the term 'inspiration'''.

Let's consider the popular 2005 Hollywood film Hitch. Spoiler alert: Alex Hitch, is a professional "date doctor" who coaches other men in the art of wooing women. While coaching one of his clients, Albert, on how to impress a client of his investment firm, Allegra, Hitch finds himself falling in love with a gossip columnist, Sara. However, none of his methods to court her had worked. While pursuing his love interest, Hitch kept his career a secret. Hitch meets a character named Vance, who wishes to use Hitch's techniques to land a one-night stand with Sara's best friend. Hitch refuses, but Vance misleads Sara into believing that Hitch had helped him. After finding out the truth about Hitch's job, Sara publishes an exposé on Hitch, resulting in the breakdown of the relationship between Albert and Allegra. In the end, Hitch tells Sara the truth about Vance, salvages the relationship between Albert and Allegra and resumes his relationship with Sara.

In 2007, Bollywood released the film Partner about a love guru, Prem, who solves the love issues of his clients. A character named Bhaskar approaches Prem for help on how to woo his boss, Priya. While helping Bhaskar, Prem falls in love with a journalist named Naina. Prem meets a character named Neil, who wishes to use Prem's techniques to land a one-night stand with Naina's best friend. Prem refuses, but Neil misleads Naina into believing that Prem had helped him. Naina finds out about Prem's job and sets out to expose him, resulting in the breakdown of the relationship between Bhaskar and Priya. In the end, Prem makes up with Naina by telling her the truth and Priya and Bhaksar are reunited.

There is no denying that the storyline of Hitch and Partner are nearly identical, apart from the inclusion of songs, which are common in Bollywood movies. According to an article by Forbes India, in 2007, Sony and Overbook Entertainment threatened to sue Eros Entertainment and K Sera Sera, for USD30-million, claiming that Partner was a direct copy of its film Hitch. This marked the "first time an international film company decided to take legal action against an Indian entertainment company for plagiarism. It is believed that the case was settled out of court."

There is also argument that Hollywood has copied the ideas of Bollywood films. In an article in the Indian Times, it is stated that the 2010 movie Leap Year was inspired by the 2007 Bollywood movie Jab We Met and the 2013 Hollywood movie Delivery Man was inspired by the 2012 Vicky Donor film. However, the inspiration behind films is not limited to Hollywood and Bollywood. It is believed that the popular 1994 Disney film The Lion King shares many similarities with the 1965 Japanese series Kimba the White Lion. Although Disney maintains that it never heard of the Japanese series before or during the making of The Lion King, there are obvious similarities in the characters and storylines of the respective productions – the most obvious being the similarities between the main characters, Kimba and Simba.

This idea/expression issue comes up frequently, particularly when it comes to drawing inspiration from previous works. In the world of music, we've previously discussed a claim of copyright infringement involving Elton John's song Nikita. In this case, a man called Guy Hobbs claimed that Elton John had copied a song that he had written called Natasha. Hobbs claimed that he had even sent the song to Elton John for consideration, and that he'd never received a response. A US court found against Hobbs, saying that the common features between the songs were too common and clichéd to enjoy copyright protection.

We've also discussed the case where the estate of the late singer Marvin Gaye sued Robin Thicke for copyright infringement relating to the hit song Blurred Lines, which was very similar to a Marvin Gaye song called Got to Give it Up. Thicke admitted that he had been inspired by Marvin Gaye, and that his song was even intended to be a tribute to a particular era, sound and genre. But he argued that there had been no copying, claiming that the common features – the high-falsetto voice, the vocal and musical layering and beat – were "commonplace musical elements'"

We've also discussed "idea cases" in the context of TV shows. There was the famous old Hughie Green case, where it was claimed that the Broadcasting Corporation of New Zealand had infringed the copyright in a TV show called Opportunity Knocks by copying various features, including particular catchphrases, contestants being introduced by sponsors, and a "clapometer" to measure audience reaction. Green's claim that he had copyright in a "dramatic work" failed because the court felt that what he had created lacked the specificity or detail for it to be performed.

In a more recent Australian case involving TV stations Channel Seven and Channel Nine, and the cooking programmes My Kitchen Rules and The Hotplate, the court was more receptive to the idea of copyright in a TV show format. The judge was prepared to accept that "the choice and arrangements of plots, characters and situations may create their own dramatic effect independent of the language in which such matters are ultimately conveyed". The judge also accepted that in this case the formats of the programmes seemed to be "very similar". Yet, the judge refused to grant an interim injunction because no case had been made for immediate relief.

Hollywood film companies will no doubt be very pleased with the Indian ruling on the films Knockout and Phone Booth. But idea/expression cases remain very tricky, and will always be difficult to predict. As more films are released in Hollywood and Bollywood, it will be interesting to see how much drawing on inspiration from previous works can affect copyright claims and how much of a change in storyline will suffice to prevent copyright infringement.

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