Filming “back-to-back” refers to the practice of filming two or more movies as one production, reducing costs and time.
Trilogies are common in the film industry, particularly in science fiction, fantasy, action, horror, thriller, and genre adventure. Production companies may choose, if the first film is a financial success, to green-light a second and a third film at the same time and film them back-to-back. In a case where the film is a movie, these installments will usually be filmed back-to-back.
In modern filmmaking , the entire cast and crew for each film are assembled from scratch for each project, and each of them is complete.  Almost all participants in the industry are freelancers , who move on to the next, and do not have much loyalty to any particular studio, as long as they get paid.
This differs from the old studio system in which large numbers of cast and crew work on their payrolls under long-term contracts. To be a analogy factory, studios transitioned from one to another, to one after another, to one after the other, to build and disassemble separate assembly lines for each single movie. 
The advantage of the system lathing Is That movie studios no follow-have to bother with paying Either people arent Who Involved in a current movie production gold with green-lighting movies very frequently so as to Efficiently feat sunk costs In Their human resources. However, this film may be unavailable because it is a film for that particular time. In turn, for every single movie studios (and Ultimately Their Investors, Shareholders, gold backers) end up bearing massive transaction costsbecause they are not only at the right time, but at the right time, and if they do not get that person, they have to scramble to locate a satisfactory substitute. All successful directors and producers have some favorite cast and crew members whom they prefer to work with, but that’s not to help the studio if that perfect character actor, costume designer, or music composer is already fully booked.
Therefore, if you have a film, you have a film with a particular cast, a crew and a storyline, one way to minimize these transactions costs is as much as possible ( before anyone dies, retrieves, or does something else that allows them to command an even higher fee) and sign them to a single production that will be edited, released, and promoted as multiple movies. This also minimizes the problem of stars visibly aging between sequels that do not have significant time gaps written in between them.
- Superman: The Movie and Superman II were filmed simultaneously in 1977 to be a two-part epic. However, due to off-screen difficulties between the producers and the director, production on the film was stopped in December 1978 release. Filming on Superman II resumed in 1979 with a new director, and was released in Australia in December 1980 and in the UK and US in 1981.
- After the 1985 movie Back to the Future Part II was in production , the two sequels Back to the Future Part II and Back to the Future Part III were in production from February 1989 to March 1990 some of the filming of the third movie overlapping with the second.
- The Lord of the Rings trilogy Was filmed Entirely over 274 days in New Zealand from October 1999 up to December 2000 with pickup shots done prior To Each movie’s theatrical release from 2001 to 2003.
- The Matrix Reloaded and The Matrix Revolutions were filmed back-to-back and released six months ago, in May 2003 and November 2003.
- Kill Bill was filmed as one film and split into two ‘volumes’, released six months apart in 2003 and 2004.
- Pirates of the Caribbean: Dead Man’s Chest and Pirates of the Caribbean: The World’s End was filmed back-to-back from February 2005 until January 2007, and released in July 2006 and May 2007.
- Harry Potter and the Deathly Hallows – Part 1 and Part 2 were filmed entirely from February 2009 to June 2010.
- Like The Lord of the Rings , The Hobbit trilogy was shot back-to-back in New Zealand from March 2011 until July 2012.
- The canceled Spider-Man 4 and the fifth film in the series were considered for back-to-back production.
- Fifty Shades Darker and Fifty Shades Freed were filmed back to back from February 2016 to July 2016. The two films were released a year ago, in February 2017 and February 2018 respectively.
- The four as-yet-untitled sequels to Avatar are being filmed back-to-back in two-two movie blocks. 
- Avengers: Infinity War and its sequel are being filmed back-to-back, with each respective film being released on 2018 and 2019. Both are entitled to share the same title with a “Part 1” and “Part 2” subtitle, but this has been changed so only the 2018 movie will hold that title. The title for the 2019 movie has yet to be announced.
- List of movies produced back-to-back
- List of movies split into multiple parts
- ^ Jump up to:a b Steven Bingen, (2014). Warner Bros .: Hollywood’s Ultimate Backlot . Lanham, MD: Rowman & Littlefield. p. 198. ISBN 9781589799622 .
- Jump up^ Dalglish, Sean. “Avatar Movies To Be Filmed Back-to-Back” .